Piperazinyl and diazapanyl benzamides and benzthioamides

ABSTRACT

Substituted piperazinyl and diazepanyl benzamides and benzthioamides of formula (I), compositions containing them, and methods of making and using them to treat histamine-mediated conditions.

Provisional Application No. 60/420,495, filed Oct. 23, 2002, herebyincorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The research and development of the invention described below was notfederally sponsored.

FIELD OF THE INVENTION

The present invention relates to piperazinyl and diazepanyl benzamidesand benzthioamides, their synthesis and their use, for example, for thetreatment of disorders and conditions mediated by the histaminereceptor.

BACKGROUND OF THE INVENTION

Histamine {2-(imidazol-4-yl)ethylamine} is a transmitter substance.Histamine exerts a physiological effect via multiple distinct G-proteincoupled receptors. It plays a role in immediate hypersensitivityreactions and is released from mast cells following antigen IgE antibodyinteraction. The actions of released histamine on the vasculature andsmooth muscle system account for the symptoms of the allergic response.These actions occur at the H₁ receptor (Ash, A. S. F. and Schild, H. O.,Br. J. Pharmac. Chemother. 1966, 27:427-439) and are blocked by theclassical antihistamines (e.g. diphenhydramine). Histamine is also animportant regulator of gastric acid secretion through its action onparietal cells. These effects of histamine are mediated via the H₂receptor (Black, J. W. et al., Nature 1972, 236:385-390) and are blockedby H₂ receptor antagonists (e.g. cimetidine). The third histaminereceptor —H₃— was first described as a presynaptic autoreceptor in thecentral nervous system (CNS) (Arrang, J.-M. et al., Nature 1983,302:832-837) controlling the synthesis and release of histamine. Recentevidence has emerged showing that H₃ receptors are also locatedpresynaptically as heteroreceptors on serotonergic, noradrenergic,dopaminergic, cholinergic, and GABAergic (gamma-aminobutyric acidcontaining) neurons. These H₃ receptors have also recently beenidentified in peripheral tissues such as vascular smooth muscle.Consequently there are many potential therapeutic applications forhistamine H₃ agonists, antagonists, and inverse agonists. (See: “TheHistamine H ₃ Receptor—A Target for New Drugs”, Leurs, R., andTimmerman, H., (Eds.), Elsevier, 1998; Morisset, S. et al., Nature 2000,408:860-864.) A fourth histamine receptor —H₄— was recently described byOda, T. et al. (J. Biol. Chem. 2000, 275(47):36781-36786).

The potential use of histamine H₃ agonists in sleep/wake andarousal/vigilance disorders is suggested based on animal studies (Lin,J.-S. et al., Brain Res. 1990, 523:325-330; Monti, J. M. et al., Eur. J.Pharmacol. 1991, 205:283-287). Their use in the treatment of migrainehas also been suggested (McLeod, R. L. et al., Soc. Neurosci. Abstr.1996, 22:2010) based on their ability to inhibit neurogenicinflammation. Other applications could be a protective role inmyocardial ischemia and hypertension where blockade of norepinephrinerelease is beneficial (Imamura, M. et al., J. Pharmacol. Exp. Ther.1994, 271(3):1259-1266). It has been suggested that histamine H₃agonists may be beneficial in asthma due to their ability to reducenon-adrenergic non-cholinergic (NANC) neurotransmission in airways andto reduce microvascular leakage (Ichinose, M. and Barnes, P. J., Eur. J.Pharmacol. 1989, 174:49-55).

Several indications for histamine H₃ antagonists and inverse agonistshave similarly been proposed based on animal pharmacology experimentswith known histamine H₃ antagonists (e.g. thioperamide). These includedementia, Alzheimer's disease (Panula, P. et al., Soc. Neurosci. Abstr.1995, 21:1977), epilepsy (Yokoyama, H. et al., Eur. J. Pharmacol. 1993,234:129-133), narcolepsy, eating disorders (Machidori, H. et al., BrainRes. 1992, 590:180-186), motion sickness, vertigo, attention deficithyperactivity disorders (ADHD), learning and memory (Barnes, J. C. etal., Soc. Neurosci. Abstr. 1993, 19:1813), and schizophrenia (Schlicker,E. and Marr, I., Naunyn-Schmiedeberg's Arch. Pharmacol. 1996,353:290-294). (Also see: Stark, H. et al., Drugs Future 1996,21(5):507-520; and Leurs, R. et al., Prog. Drug Res. 1995, 45:107-165and references cited therein.) Histamine H₃ antagonists, alone or incombination with a histamine H₁ antagonist, are reported to be usefulfor the treatment of upper airway allergic response (U.S. Pat. Nos.5,217,986; 5,352,707 and 5,869,479). Recently, a histamine H₃ antagonist(GT-2331) was identified and is being developed by Gliatech Inc.(Gliatech Inc. Press Release Nov. 5, 1998; Bioworld Today, Mar. 2, 1999)for the treatment of CNS disorders.

As noted, the literature related to histamine H₃ ligands has beencomprehensively reviewed (“The Histamine H₃ Receptor—A Target for NewDrugs”, Leurs, R. and Timmerman, H., (Eds.), Elsevier, 1998). Withinthis reference the medicinal chemistry of histamine H₃ agonists andantagonists was reviewed (see Krause, M. et al., and Phillips, J. G. andAli, S. M., respectively). The importance of an imidazole moietycontaining only a single substitution in the 4-position was notedtogether with the deleterious effects of additional substitution onactivity. Particularly, methylation of the imidazole ring at any of theremaining unsubstituted positions was reported to strongly decreaseactivity. Additional publications support the hypothesis that animidazole function is essential for high affinity histamine H₃ receptorligands (see Ali, S. M. et al., J. Med. Chem. 1999, 42:903-909, andStark, H. et al., and references cited therein). However manyimidazole-containing compounds are substrates for histamine methyltransferase, the major histamine metabolizing enzyme in humans, whichleads to shortened half-lives and lower bioavailability (see Rouleau, A.et al., J. Pharmacol. Exp. Ther. 1997, 281(3):1085-1094). In addition,imidazole-containing drugs, via their interaction with the cytochromeP450 monooxygenase system, can be targets of unfavorablebiotransformations due to enzyme induction or enzyme inhibition (see:Kapetanovic, I. M. and Kupferberg, H. J., Drug Metab. Dispos. 1984,12(5):560-564; Sheets, J. J. and Mason, J. I., Drug Metab. Dispos. 1984,12(5):603-606; Back, D. J. and Tjia, J. F., Br. J. Pharmacol. 1985,85:121-126; Lavrijsen, K. et al., Biochem. Pharmacol. 1986,35(11):1867-1878; Albengres, E. et al., Drug Safety, 1998, 18(2):83-97).The poor blood brain barrier penetration of earlier histamine H₃receptor ligands may also be associated with the imidazole fragment(Ganellin, C. R. et al., Arch. Pharm. Pharm. Med. Chem. (Weinheim, Ger.)1998, 331:395-404).

More recently, several publications have described histamine H₃ ligandsthat do not contain an imidazole moiety, for example: Ganellin, C. R. etal.; Walczynski, K. et al., Arch. Pharm. Pharm. Med. Chem. (Weinheim,Ger.) 1999, 332:389-398; Walczynski, K. et al., Farmaco 1999,54:684-694; Linney, I. D. et al., J. Med. Chem. 2000, 43:2362-2370;Tozer, M. J. and Kalindjian, S. B., Exp. Opin. Ther. Patents 2000,10:1045-1055; U.S. Pat. No. 5,352,707; PCT Application WO 99/42458, Aug.26, 1999; PCT Application WO 02/076925; and European Patent Application0978512, Feb. 9, 2000.

The compounds of the present invention do not contain the imidazolemoiety, and its inherent liabilities, and yet maintain potency at thehuman H₃ receptor as determined by receptor binding to the humanhistamine H₃ receptor (see Lovenberg, T. W. et al., Mol. Pharmacol.1999, 55:1101-1107). Screening using the human receptor is particularlyimportant for the identification of new therapies for the treatment ofhuman disease. Conventional binding assays are determined using ratsynaptosomes (Garbarg, M. et al., J. Pharmacol. Exp. Ther. 1992,263(1):304-310), rat cortical membranes (West, R. E. et al., Mol.Pharmacol. 1990, 38:610-613), and guinea pig brain (Korte, A. et al.,Biochem. Biophys. Res. Commun. 1990, 168(3):979-986). Only limitedstudies have been performed previously using human tissue but theseallude to significant differences in the pharmacology of rodent andprimate receptors (West, R. E. et al., Eur. J. Pharmacol. 1999,377:233-239).

We now describe a series of piperazinyl and diazepanyl benzamides andbenzthioamides with the ability to modulate the activity of thehistamine receptor, specifically the H₃ receptor, without the inherentproblems associated with the presence of an imidazolyl moiety.

SUMMARY OF THE INVENTION

The present invention is directed to pharmaceutically active piperazinyland diazepanyl benzamides and benzthioamides, methods of making them,and methods of using them. The invention features compounds of formula(I):

wherein

-   R¹ is C₁₋₁₀ alkyl, C₃₋₈ alkenyl, C₃₋₈ cycloalkyl, (C₃₋₈    cycloalkyl)C₁₋₆ alkyl, (C₃₋₈ cycloalkyl)C₃₋₈ alkenyl, or (C₁₋₈    alkylcarbonyl)C₁₋₈ alkyl;-   n is 1 or 2;-   X is O or S;-   one of R², R³ and R⁴ is G and the other two independently are    hydrogen, fluoro, chloro, bromo, nitro, trifluoromethyl, methyl, or    C₁₋₃alkoxy;-   G is LQ;-   L is unbranched —(CH₂)_(m)— wherein m is an integer from 1 to 7    (preferably m is 1 to 4, more preferably m is 1);-   Q is NR⁸R⁹ wherein R⁸ is independently selected from hydrogen, C₁₋₆    alkyl, C₃₋₆ alkenyl, 3-9 membered carbocyclyl, 3-12 membered    heterocyclyl (preferably 5-9 or 5-8-membered heterocyclyl), phenyl,    (6-9-membered heterocyclyl)C₁₋₆ alkylene, and (phenyl)C₁₋₆ alkylene;    and R⁹ is independently selected from C₁₋₆ alkyl, C₃₋₆ alkenyl, 6-9    membered carbocyclyl, 3-12 membered heterocyclyl (preferably 5-9 or    5-8-membered heterocyclyl), phenyl, (6-9-membered heterocyclyl)C₁₋₆    alkylene, and (phenyl)C₁₋₆ alkylene; or-   Q is a saturated 3-12 membered N-linked heterocyclyl, wherein, in    addition to the N-linking nitrogen, the 3-12 membered heterocyclyl    may optionally contain between 1 and 3 additional heteroatoms    independently selected from O, S, and NH;-   wherein Q is optionally substituted with 1-3 substituents    independently selected from the group consisting of hydroxy, halo,    carboxamide, C₁₋₆ alkyl, 5-9 membered or 6-9 membered heterocyclyl,    —N(C₁₋₆ alkyl)(5-9 membered or 6-9 membered heterocyclyl), —NH(5-9    membered or 6-9 membered heterocyclyl), —O(5-9 or 6-9 membered    heterocyclyl), (5-9 membered or 6-9 membered heterocyclyl)C₁₋₃    alkylene, C₁₋₆ alkoxy, (C₃₋₆ cycloalkyl)-O—, phenyl, (phenyl)C₁₋₃    alkylene, and (phenyl)C₁₋₃ alkylene-O—, where each of above    heterocyclyl, phenyl, and alkyl groups may be optionally substituted    with from 1 to 3 substituents independently selected from    trifluoromethyl, methoxy, halo, nitro, cyano, hydroxy, and C₁₋₃    alkyl;-   provided however that when R¹ is methyl, G is not    piperidin-1-ylmethyl; and-   wherein each of the above alkyl, alkylene, alkenyl, heterocyclyl,    cycloalkyl, carbocyclyl, and aryl groups may each be independently    and optionally substituted with between 1 and 3 substituents    independently selected from trifluoromethyl, methoxy, halo, amino,    nitro, hydroxy, and C₁₋₃ alkyl;    or a pharmaceutically acceptable salt, ester, tautomer, solvate or    amide thereof.

The invention also features a pharmaceutical composition comprising acompound of the invention and a pharmaceutically acceptable carrier; andmethods of preparing or formulating such compositions. A composition ofthe invention may further include more than one compound of theinvention, or a combination therapy (combination formulation orcombination of differently formulated active agents).

The invention also provides methods of treating certain conditions anddiseases, each of which methods includes administering a therapeuticallyeffective (or jointly effective) amount of a compound or composition ofthe invention to a subject in need of such treatment. The disclosedcompounds are useful in methods for treating or preventing neurologicdisorders including sleep/wake and arousal/vigilance disorders (e.g.insomnia and jet lag), attention deficit hyperactivity disorders (ADHD),learning and memory disorders, cognitive dysfunction, migraine,neurogenic inflammation, dementia, mild cognitive impairment(pre-dementia), Alzheimer's disease, epilepsy, narcolepsy, eatingdisorders, obesity, motion sickness, vertigo, schizophrenia, substanceabuse, bipolar disorders, manic disorders and depression, as well asother histamine H₃ receptor mediated disorders such as upper airwayallergic response, asthma, itch, nasal congestion and allergic rhinitisin a subject in need thereof. For example, the invention featuresmethods for preventing, inhibiting the progression of, or treating upperairway allergic response, asthma, itch, nasal congestion and allergicrhinitis.

In yet another embodiment, the disclosed compounds may be used in acombination therapy method including administering a jointly effectivedose of an H₃ antagonist and administering a jointly effective dose of ahistamine H₁ antagonist, such as loratidine (CLARITIN™), desloratidine(CLARINEX™), fexofenadine (ALLEGRA™) and cetirizine (ZYRTEC™), for thetreatment of allergic rhinitis, nasal congestion, and allergiccongestion.

In yet another embodiment, the disclosed compounds may be used in acombination therapy method, including administering a jointly effectivedose of an H₃ antagonist and administering a jointly effective dose of aneurotransmitter re-uptake blocker, such as a selective serotoninre-uptake inhibitor (SSRI) or a non-selective serotonin, dopamine ornorepinephrine re-uptake inhibitor, including fluoxetine (PROZAC™),sertraline (ZOLOFT™), paroxetine (PAXIL™) and amitryptyline, for thetreatment of depression, mood disorders or schizophrenia.

Additional features and advantages of the invention will become apparentfrom the detailed description and examples below, and the appendedclaims.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides phenylpiperidine compounds useful for thetreatment of disorders and conditions modulated by a histamine receptor.

A. TERMS

Certain terms are defined below and by their usage throughout thisdisclosure.

As used herein, “C_(a-b)” (where a and b are integers) refers to aradical containing from a to b carbon atoms inclusive. For example, C₁₋₃denotes a radical containing 1, 2 or 3 carbon atoms.

As used herein, “halo” or “halogen” shall mean monovalent radicals ofchlorine, bromine, fluorine and iodine.

As used herein, the term “alkyl”, whether used alone or as part of asubstituent group, shall include straight and branched saturated carbonchains. For example, alkyl radicals include methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl and the like.Unless otherwise noted, “lower” when used with alkyl means a carbonchain composition of 1-4 carbon atoms. “Alkylene” refers to a bivalenthydrocarbyl group, such as methylene (—CH₂—), ethylene (—CH₂—CH₂—) orpropylene (—CH₂CH₂CH₂—), and so on.

As used herein, unless otherwise noted, “alkenyl” shall mean an alkylenegroup with at least two hydrogen atoms replaced with a pi bond to form acarbon-carbon double bond, such as propenyl, butenyl, pentenyl, and soon. Where the alkenyl group is R⁸ or R⁹, the open radical (point ofattachment to the rest of the molecule) is on sp³ carbon, as illustratedby allyl, and the double bond or bonds is therefore at least alpha (ifnot beta, gamma, etc.) to the open radical.

As used herein, “alkylidene” refers to a saturated or unsaturated,branched, straight-chain or cyclic divalent hydrocarbon radical derivedby removal of two hydrogen atoms from the same carbon atom of a parentalkane, alkene or alkyne. The divalent radical center forms a doublebond with a single atom on the rest of the molecule. Typical alkylideneradicals include, but are not limited to, ethanylidene; propylidenessuch as propan-1-ylidene, propan-2-ylidene, cyclopropan-1-ylidene;butylidenes such as butan-1-ylidene, butan-2-ylidene,2-methyl-propan-1-ylidene, cyclobutan-1-ylidene; and the like.

As used herein, unless otherwise noted, “alkoxy” shall denote an oxygenether radical of the above-described straight or branched chain alkylgroups. For example, methoxy, ethoxy, n-propoxy, sec-butoxy, t-butoxy,n-hexyloxy and the like.

As used herein, unless otherwise noted, “cycloalkyl” shall denote athree- to eight-membered, saturated monocyclic carbocyclic ringstructure. Suitable examples include cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl.

As used herein, unless otherwise noted, “cycloalkenyl” shall denote athree- to eight-membered, partially unsaturated, monocyclic, carbocyclicring structure, wherein the ring structure contains at least one doublebond. Suitable examples include cyclohexenyl, cyclopentenyl,cycloheptenyl, cyclooctenyl, cyclohex-1,3-dienyl and the like.

As used herein, unless otherwise noted, “aryl” shall refer tocarbocyclic aromatic groups such as phenyl, naphthyl, and the like.Divalent radicals include phenylene (—C₆H₄—) which is preferablyphen-1,4-diyl, but may also be phen-1,3-diyl.

As used herein, unless otherwise noted, “aralkyl” shall mean any alkylgroup substituted with an aryl group such as phenyl, naphthyl, and thelike. Examples of aralkyls include benzyl, phenethyl, and phenylpropyl.

As used herein, unless otherwise noted, “carbocyclyl” shall mean anycyclic group consisting of 3-12 carbon atoms, and preferably 6-9 carbonatoms, in the skeleton ring or rings, if the carbocycle is a fused orspiro bicyclic or tricyclic group. A carbocycle may be saturated,unsaturated, partially unsaturated, or aromatic. Examples includecycloalkyl, cycloalkenyl, cycloalkynyl; specific examples includephenyl, benzyl, indanyl, and biphenyl. A carbocycle may havesubstituents that are not carbon or hydrogen, such as hydroxy, halo,halomethyl, and so on as provided elsewhere herein.

As used herein, unless otherwise noted, the terms “heterocycle”,“heterocyclyl” and “heterocyclo” shall denote any three-, four-, five-,six-, seven-, or eight-membered monocyclic, nine- or ten-memberedbicyclic, or thirteen- or fourteen-membered tricyclic ring structurecontaining at least one heteroatom moiety selected from the groupconsisting of NH, O, SO, SO₂, (C═O), and S, and preferably NH, O, or S,optionally containing one to four additional heteroatoms in each ring.In some embodiments, the heterocyclyl contains between 1 and 3 orbetween 1 and 2 additional heteroatoms. Unless otherwise specified, aheterocyclyl may be saturated, partially unsaturated, aromatic orpartially aromatic. The heterocyclyl group may be attached at anyheteroatom or carbon atom that results in the creation of a stablestructure.

Exemplary monocyclic heterocyclic groups can include pyrrolidinyl,pyrrolyl, indolyl, pyrazolyl, oxetanyl, pyrazolinyl, imidazolyl,imidazolinyl, imidazolidinyl, oxazolyl, oxazolidinyl, isoxazolinyl,isoxazolyl, thiazaolyl, thiadiazolyl, thiazolidinyl, isothiazolyl,isothiazolidinyl, furyl, tetrahydrofuryl, thienyl, oxadiazolyl,piperidinyl, piperazinyl, 2-oxopiperazinyl, 2-oxopiperidinyl,2-oxopyrrolidinyl, 2-oxazepinyl, azepinyl, hexahydroazepinyl,4-piperidinyl, pyridyl, N-oxo-pyridyl, pyrazinyl, pyrimidinyl,pyridazinyl, tetrahydropyranyl, tetrahydrothiopyranyl,tetrahydrothiopyranyl sulfone, morpholinyl, thiomorpholinyl,thiomorpholinyl sulfoxide, thiomorpholinyl sulfone, 1,3-dixolane andtetrahydro-1,1-dioxothienyl, dioxanyl, isothiazolidinyl, thietanyl,thiiranyl, triazinyl, triazolyl, tetrazolyl, azetidinyl and the like.

For example, where Q is a saturated 3-12 membered N-linked heterocyclyl,Q necessarily contains at least one nitrogen, and the carbon atoms aresp³ hybridized. Where Q is a fused bicyclic heterocyclyl, the carbonatoms of the ring linked to L is sp³ hybridized, provided the adjacentring (and the common carbon atoms) may be sp², such as an indanyl whereone of the carbon atoms has been replaced with nitrogen.

In general, exemplary bicyclic heterocyclyls include benzthiazolyl,benzoxazolyl, benzoxazinyl, benzothienyl, quinuclidinyl, quinolinyl,quinolinyl-N-oxide, tetrahydroisoquinolinyl, isoquinolinyl,benzimidazolyl, benzopyranyl, indolizinyl, benzofuryl, chromonyl,coumarinyl, cinnolinyl, quinoxalinyl, indazolyl, pyrrolopridyl,furopyridinyl (such as furo{2,3-c}pyridinyl, furo{3,1-b}pyridinyl), orfuro{2,3-b}pyridinyl), dihydroisoindolyl, dihydroquinazolinyl (such as3,4-dihydro-4-oxo-quinazolinyl), tetrahydroquinolinyl (such as1,2,3,4-tetrahydroquinolinyl), tetrahydroisoquinolinyl(such as1,2,3,4-tetrahydroisoquiunolinyl), benzisothiazolyl, benzisoxazolyl,benzodiazinyl, benzofurazanyl, benzothiopyranyl, benzotriazolyl,benzpyrazolyl, dihydrobenzofuryl, dihydrobenzothienyl,dihydrobenzothiopyranyl, dihydrobenzothiopyranyl sulfone,dihydrobenzopyranyl, indolinyl, isoindolyl, tetrahydroindoazolyl (suchas 4,5,6,7-tetrahydroindazolyl), isochromanyl, isoindolinyl,naphthyridinyl, phthalazinyl, piperonyl, purinyl, pyridopyridyl,quinazolinyl, tetrahydroquinolinyl, thienofuryl, thienopyridyl,thienothienyl,

and the like.

Exemplary tricyclic heterocylclic groups include acridinyl,phenoxazinyl, phenazinyl, phenothiazinyl, carbozolyl, perminidinyl,phenanthrolinyl, carbolinyl, naphthothienyl, thianthrenyl, and the like.

Preferred heterocyclyl groups include morpholinyl, thiomorpholinyl,piperidinyl, piperazinyl, pyrrolidinyl, pyrimidinyl, pyridyl, pyrrolyl,imidazolyl, oxazolyl, isoxazolyl, acridinyl, azepinyl,hexahydroazepinyl, azetidinyl, indolyl, isoindolyl, thiazolyl,thiadiazolyl, quinolinyl, isoquinolinyl, 1,2,3,4-tetrahydroquinolinyl,1,3,4-trihydroisoquinolinyl, 4,5,6,7-tetrahydroindadolyl, benzoxazinyl,benzoaxzolyl, benzthiazolyl, benzimidazolyl, tetrazolyl, oxadiazolyl,

As used herein, unless otherwise noted, the term “heterocyclyl-alkyl” or“heterocyclyl-alkylene” shall denote any alkyl group substituted with aheterocyclyl group, wherein the heterocycly-alkyl group is bound throughthe alkyl portion to the central part of the molecule. Suitable examplesof heterocyclyl-alkyl groups include, but are not limited topiperidinylmethyl, pyrrolidinylmethyl, piperidinylethyl,piperazinylmethyl, pyrrolylbutyl, piperidinylisobutyl, pyridylmethyl,pyrimidylethyl, and the like.

When a particular group is “substituted” (e.g., alkyl, alkylene,cycloalkyl, aryl, heterocyclyl, heteroaryl), that group may have one ormore substituents, preferably from one to five substituents, morepreferably from one to three substituents, most preferably from one totwo substituents, independently selected from the list of substituents.

It is intended that the definition of any substituent or variable at aparticular location in a molecule be independent of its definitionselsewhere in that molecule. It is understood that substituents andsubstitution patterns on the compounds of this invention can be selectedby one of ordinary skill in the art to provide compounds that arechemically stable and that can be readily synthesized by techniquesknown in the art as well as those methods set forth herein.

Under standard nomenclature used throughout this disclosure, theterminal portion of the designated side chain is described first,followed by the adjacent functionality toward the point of attachment.Thus, for example, a “phenyl(alkyl)amido(alkyl)” substituent refers to agroup of the formula

The term “subject” as used herein, refers to an animal, preferably amammal, most preferably a human, who has been the object of treatment,observation or experiment.

The term “therapeutically effective amount” as used herein, means thatamount of active compound or pharmaceutical agent that elicits thebiological or medicinal response in a tissue system, animal or humanthat is being sought by a researcher, veterinarian, medical doctor orother clinician, which includes prevention, inhibition of onset, oralleviation of the symptoms of the disease or disorder being treated.

As used herein, the term “composition” is intended to encompass aproduct comprising the specified ingredients in the specified amounts,as well as any product which results, directly or indirectly, fromcombinations of the specified ingredients in the specified amounts.

Abbreviations used in the specification, particularly in the Schemes andExamples, are as follows DBAD = Di-tert-butyl azodicarboxylate DCE =1,2-dichloroethane DCM = Dichloromethane DEAD = Diethyl azodicarboxylateDMA = N,N-dimethylacetamide DMAP = 4-N,N-dimethylamino- pyridine DME =1,2-dimethoxyethane DMF = Dimethylformamide DMSO = Dimethylsulfoxide RT= Room temperature TEA = Triethylamine TFA = Trifluoroacetic acid THF =Tetrahydrofuran

B. COMPOUNDS

The invention features compounds of formula (I):

wherein

-   R¹ is C₁₋₁₀ alkyl, C₃₋₈ alkenyl, C₃₋₈ cycloalkyl, (C₃₋₈    cycloalkyl)C₁₋₆ alkyl, (C₃₋₈ cycloalkyl)C₃₋₈ alkenyl, or (C₁₋₈    alkylcarbonyl)C₁₋₈ alkyl;-   n is 1 or 2;-   X is O or S;-   one of R², R³ and R⁴ is G and the other two independently are    hydrogen, fluoro, chloro, bromo, nitro, trifluoromethyl, methyl, or    C₁₋₃alkoxy;-   G is LQ;-   L is unbranched —(CH₂)_(m)— wherein m is an integer from 1 to 7;-   Q is NR⁸R⁹ wherein R⁸ is independently selected from hydrogen, C₁₋₆    alkyl, C₃₋₆ alkenyl, 3-9 membered carbocyclyl, 3-12 membered    heterocyclyl (preferably 5-9 or 5-8-membered heterocyclyl), phenyl,    (6-9-membered heterocyclyl)C₁₋₆ alkylene, and (phenyl)C₁₋₆ alkylene;    and R⁹ is independently selected from C₁₋₆ alkyl, C₃₋₆ alkenyl, 6-9    membered carbocyclyl, 3-12 membered heterocyclyl (preferably 5-9 or    5-8-membered heterocyclyl), phenyl, (6-9-membered heterocyclyl)C₁₋₆    alkylene, and (phenyl)C₁₋₆ alkylene; or-   Q is a saturated 3-12 membered N-linked heterocyclyl, wherein, in    addition to the N-linking nitrogen, the 3-12 membered heterocyclyl    may optionally contain between 1 and 3 additional heteroatoms    independently selected from O, S, and NH;-   wherein Q is optionally substituted with 1-3 substituents    independently selected from the group consisting of hydroxy, halo,    carboxamide, C₁₋₆ alkyl, 5-9 membered or 6-9 membered heterocyclyl,    —N(C₁₋₆ alkyl)(5-9 membered or 6-9 membered heterocyclyl), —NH(5-9    membered or 6-9 membered heterocyclyl), —O(5-9 or 6-9 membered    heterocyclyl), (5-9 membered or 6-9 membered heterocyclyl)C₁₋₃    alkylene, C₁₋₆ alkoxy, (C₃₋₆ cycloalkyl)-O—, phenyl, (phenyl)C₁₋₃    alkylene, and (phenyl)C₁₋₃ alkylene-O—, where each of above    heterocyclyl, phenyl, and alkyl groups may be optionally substituted    with from 1 to 3 substituents independently selected from    trifluoromethyl, methoxy, halo, nitro, cyano, hydroxy, and C₁₋₃    alkyl;-   provided however that when R¹ is methyl, G is not    piperidin-1-ylmethyl; and-   wherein each of the above alkyl, alkylene, alkenyl, heterocyclyl,    cycloalkyl, carbocyclyl, and aryl groups may each be independently    and optionally substituted with between 1 and 3 substituents    independently selected from trifluoromethyl, methoxy, halo, amino,    nitro, hydroxyl, and C₁₋₃ alkyl;-   or a pharmaceutically acceptable salt, ester, tautomer, solvate or    amide thereof.

Preferred compounds of formula (I) include those wherein:

(a) n is 1;

(b) R¹ is C₁₋₁₀ alkyl (preferably branched);

(c) R¹ is branched C₃₋₅ alkyl;

(d) one of R², R³ and R⁴ is G; (preferably one of R³ and R⁴ is G)

(e) R⁴ is G;

(f) L is unbranched —(CH₂)_(m)—, wherein m is an integer from 1 to 4;

(g) L is —CH₂—;

(h) Q is a saturated N-linked nitrogen-containing heterocyclyl;

(i) Q is substituted or unsubstituted piperidinyl, diazepanyl, azepanyl,decahydroisoquinolin-2-yl, piperazinyl, pyrrolinyl, pyrrolidinyl,thiomorpholinyl, or morpholinyl;

(j) Q is unsubstituted diazepanyl, azepanyl, morpholinyl,decahydroisoquinolin-2-yl, piperidinyl, or pyrrolidinyl;

(k) substituted Q are selected from N—(C₁₋₆ alkyl)piperazinyl,N-phenyl-piperazinyl, 1,3,8-triaza-spiro{4.5}decyl, and1,4-dioxa-8-aza-spiro{4.5}decyl;

(l) Q is a monovalent radical of an amine selected from aziridine,1,4,7-trioxa-10-aza-cyclododecane, thiazolidine,1-phenyl-1,3,8-triaza-spiro{4.5}decan-4-one, piperidine-3-carboxylicacid diethylamide, 1,2,3,4,5,6-hexahydro-{2,3′}bipyridinyl,4-(3-trifluoromethyl-phenyl)-piperazine, 2-piperazin-1-yl-pyrimidine,piperidine-4-carboxylic acid amide, methyl-(2-pyridin-2-yl-ethyl)-amine,{2-(3,4-dimethoxy-phenyl)-ethyl}-methyl-amine, thiomorpholinyl,allyl-cyclopentyl-amine, {2-(1H-indol-3-yl)-ethyl}-methyl-amine,1-piperidin-4-yl-1,3-dihydro-benzoimidazol-2-one,2-(piperidin-4-yloxy)-pyrimidine, piperidin-4-yl-pyridin-2-yl-amine,phenylamine, and pyridin-2-ylamine;

(m) Q is selected from diazepanyl, azepanyl, morpholinyl, piperidinyl,and pyrrolidinyl, optionally substituted with between 1 and 3substituents independently selected from hydroxy, halo, carboxamide,C₁₋₆ alkyl, 5-9 membered or 6-9 membered heterocyclyl, —N(C₁₋₆alkyl)(5-9 membered or 6-9 membered heterocyclyl), —NH(5-9 membered or6-9 membered heterocyclyl), —O(5-9 or 6-9 membered heterocyclyl), (5-9membered or 6-9 membered heterocyclyl)C₁₋₃ alkylene, C₁₋₆ alkoxy, (C₃₋₆cycloalkyl)-O—, phenyl, (phenyl)C₁₋₃ alkylene, and (phenyl)C₁₋₃alkylene-O—, where each of above heterocyclyl, phenyl, and alkyl groupsmay be optionally substituted with from 1 to 3 substituentsindependently selected from trifluoromethyl, methoxy, halo, nitro,cyano, hydroxy, and C₁₋₃ alkyl;

(n) Q is substituted with a substituent comprising a 5-9 membered or 6-9membered heterocyclyl group selected from: pyridyl, pyrimidyl, furyl,thiofuryl, imidazolyl, (imidazolyl)C₁₋₆ alkylene, oxazolyl, thiazolyl,2,3-dihydro-indolyl, benzimidazolyl, 2-oxobenzimidazolyl,(tetrazolyl)C₁₋₆ alkylene, tetrazolyl, (triazolyl)C₁₋₆ alkylene,triazolyl, (pyrrolyl)C₁₋₆ alkylene, pyrrolidinyl, and pyrrolyl;

(o) Q is piperidinyl;

(p) R⁸ is hydrogen;

(q) R⁹ is C₁₋₆ alkyl;

(r) R⁹ is unsubstituted or substituted phenyl;

(s) R⁸ and R⁹ independently are C₁₋₆ alkyl;

(t) R⁸ and R⁹ are methyl;

(u) R⁸ and R⁹ are ethyl;

(v) R⁹ is selected from phenyl or 5-9 membered aromatic heterocyclyl,wherein said phenyl or aromatic heterocyclyl is optionally substitutedwith 1-3 substituents selected from methoxy, hydroxy, halo, nitro,cyano, trifluoromethyl, and C₁₋₃ alkyl;

(w) R⁹ is selected from substituted or unsubstituted phenyl, pyridyl,pyrimidyl, furyl, thiofuryl, imidazolyl, (imidazolyl)C₁₋₆ alkylene,oxazolyl, thiazolyl, 2,3-dihydro-indolyl, benzimidazolyl,2-oxobenzimidazolyl, (tetrazolyl)C₁₋₆ alkylene, tetrazolyl,(triazolyl)C₁₋₆ alkylene, triazolyl, (pyrrolyl)C₁₋₆ alkylene,pyrrolidinyl, and pyrrolyl;

(x) R⁹ is substituted or unsubstituted pyridyl;

(y) X is O; and

(z) combinations of (a) through (z) above.

Examples of compounds of the invention include:

-   (4-{[Ethyl-(2-methoxy-ethyl)-amino]-methyl}-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone;-   (4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;-   (4-Azepan-1-ylmethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;-   (4-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;-   (4-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;-   (4-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone;-   (4-Butyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanone;-   (4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Diethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Dimethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Dimethylaminomethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-(3-morpholin-4-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(3-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-{[(2-methoxy-ethyl)-propyl-amino]-methyl}-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-(4-thiomorpholin-4-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-{4-(4-isopropyl-piperazin-1-ylmethyl)-phenyl}-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-ethylamino)-methyl]-phenyl}-methanone;-   (4-Isopropyl-piperazin-1-yl)-[4-(pyridin-2-ylaminomethyl)-phenyl]-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-1-methyl-ethylamino)-methyl]-phenyl}-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-pyridin-2-ylamino)-methyl}-phenyl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-{4-{(5-trifluoromethyl-pyridin-2-ylamino)-methyl}-phenyl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-{4-{(6-trifluoromethyl-pyridin-3-ylamino)-methyl}-phenyl}-methanone    dihydrochloride;-   (4-Methyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-Methyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-sec-Butyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   {3-(4-Benzyl-piperidin-1-ylmethyl)-phenyl}-(4-methyl-piperazin-1-yl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-phenylaminomethyl-phenyl)-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(decahydro-isoquinolin-2-ylmethyl)-phenyl}-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanone    dihydrochloride;-   {4-(1-Methyl-heptyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanone;-   {4-(1-Methyl-heptyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   {4-(Benzylamino-methyl)-phenyl}-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   {4-(Benzylamino-methyl)-phenyl}-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;    and-   {4-{(5-Chloro-pyridin-2-ylamino)-methyl}-phenyl}-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride.

Preferred example compounds include:

-   (4-{[Ethyl-(2-methoxy-ethyl)-amino]-methyl}-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone;-   (4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;-   (4-Azepan-1-ylmethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;-   (4-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;-   (4-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;-   (4-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone;-   (4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Diethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Dimethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Dimethylaminomethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-(3-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-{[(2-methoxy-ethyl)-propyl-amino]-methyl}-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-(4-thiomorpholin-4-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-{4-(4-isopropyl-piperazin-1-ylmethyl)-phenyl}-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-ethylamino)-methyl]-phenyl}-methanone;-   (4-Isopropyl-piperazin-1-yl)-[4-(pyridin-2-ylaminomethyl)-phenyl]-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-1-methyl-ethylamino)-methyl]-phenyl}-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-{(5-trifluoromethyl-pyridin-2-ylamino)-methyl}-phenyl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-{4-{(6-trifluoromethyl-pyridin-3-ylamino)-methyl}-phenyl}-methanone    dihydrochloride;-   (4-Methyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-Methyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-sec-Butyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(decahydro-isoquinolin-2-ylmethyl)-phenyl}-methanone;-   {4-(Benzylamino-methyl)-phenyl}-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   {4-(Benzylamino-methyl)-phenyl}-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;    and-   {4-{(5-Chloro-pyridin-2-ylamino)-methyl}-phenyl}-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride.

More preferred example compounds include:

-   (4-{[Ethyl-(2-methoxy-ethyl)-amino]-methyl}-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone;-   (4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;-   (4-Azepan-1-ylmethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;-   (4-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;-   (4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Diethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Dimethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Dimethylaminomethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-(4-{[(2-methoxy-ethyl)-propyl-amino]-methyl}-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-(4-thiomorpholin-4-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-ethylamino)-methyl]-phenyl}-methanone;-   (4-Isopropyl-piperazin-1-yl)-[4-(pyridin-2-ylaminomethyl)-phenyl]-methanone;-   (4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-1-methyl-ethylamino)-methyl]-phenyl}-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(decahydro-isoquinolin-2-ylmethyl)-phenyl}-methanone;-   {4-(Benzylamino-methyl)-phenyl}-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride; and-   {4-(Benzylamino-methyl)-phenyl}-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone.

Even more preferred example compounds include:

-   (4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone    dihydrochloride;-   (4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;-   (4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone    dihydrochloride;-   (4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone    dihydrochloride;-   (4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;    and-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone.

Yet even more preferred example compounds include:

-   (4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;-   (4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;-   (4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride; and-   {4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanone    dihydrochloride.

The invention also provides compounds that are useful as syntheticintermediates of the compounds of the invention. Such compounds, whichthemselves may or may not have pharmaceutical activity, include thoseprovided in the schemes and synthetic examples.

The invention also contemplates compounds isotopically-labelled to bedetectable by positron emission tomography (PET) or single-photonemission computed tomography (SPECT) useful for studying H₃-mediateddisorders.

During any of the processes for preparation of the compounds of thepresent invention, it may be necessary and/or desirable to protectsensitive or reactive groups on any of the molecules concerned. Inaddition, compounds of the invention may be modified by using protectinggroups; such compounds, precursors, or prodrugs are also within thescope of the invention. This may be achieved by means of conventionalprotecting groups, such as those described in “Protective Groups inOrganic Chemistry”, ed. J. F. W. McOmie, Plenum Press, 1973; and T. W.Greene & P. G. M. Wuts, “Protective Groups in Organic Synthesis”, 3^(rd)ed., John Wiley & Sons, 1999. The protecting groups may be removed at aconvenient subsequent stage using methods known from the art.

Hydroxyl Protecting Groups

Protection for the hydroxyl group includes methyl ethers, substitutedmethyl ethers, substituted ethyl ethers, substitute benzyl ethers, andsilyl ethers.

Substituted Methyl Ethers

Examples of substituted methyl ethers include methyoxymethyl,methylthiomethyl, t-butylthiomethyl, (phenyldimethylsilyl)methoxymethyl,benzyloxymethyl, p-methoxybenzyloxymethyl, (4-methoxyphenoxy)methyl,guaiacolmethyl, t-butoxymethyl, 4-pentenyloxymethyl, siloxymethyl,2-methoxyethoxymethyl, 2,2,2-trichloroethoxymethyl,bis(2-chloroethoxy)methyl, 2-(trimethylsilyl)ethoxymethyl,tetrahydropyranyl, 3-bromotetrahydropyranyl, tetrahydrothiopyranyl,1-methoxycyclohexyl, 4-methoxytetrahydropyranyl,4-methoxytetrahydrothiopyranyl, 4-methoxytetrahydrothiopyranylS,S-dioxido, 1-{(2-chloro-4-methyl)phenyl}-4-methoxypiperidin-4-yl,1,4-dioxan-2-yl, tetrahydrofuranyl, tetrahydrothiofuranyl and2,3,3a,4,5,6,7,7a-octahydro-7,8,8-trimethyl-4,7-methanobenzofuran-2-yl.

Substituted Ethyl Ethers

Examples of substituted ethyl ethers include 1-ethoxyethyl,1-(2-chloroethoxy)ethyl, 1-methyl-1-methoxyethyl,1-methyl-1-benzyloxyethyl, 1-methyl-1-benzyloxy-2-fluoroethyl,2,2,2-trichloroethyl, 2-trimethylsilylethyl, 2-(phenylselenyl)ethyl,t-butyl, allyl, p-chlorophenyl, p-methoxyphenyl, 2,4-dinitrophenyl, andbenzyl.

Substituted Benzyl Ethers

Examples of substituted benzyl ethers include p-methoxybenzyl,3,4-dimethoxybenzyl, o-nitrobenzyl, p-nitrobenzyl, p-halobenzyl,2,6-dichlorobenzyl, p-cyanobenzyl, p-phenylbenzyl, 2- and 4-picolyl,3-methyl-2-picolyl N-oxido, diphenylmethyl, p,p′-dinitrobenzhydryl,5-dibenzosuberyl, triphenylmethyl, α-naphthyldiphenylmethyl,p-methoxyphenyldiphenylmethyl, di(p-methoxyphenyl)phenylmethyl,tri(p-methoxyphenyl)methyl, 4-(4′-bromophenacyloxy)phenyldiphenylmethyl,4,4′,4″-tris(4,5-dichlorophthalimidophenyl)methyl,4,4′,4″-tris(levulinoyloxyphenyl)methyl,4,4′,4″-tris(benzoyloxyphenyl)methyl,3-(Imidazol-1-ylmethyl)bis(4′,4″-dimethoxyphenyl)methyl,1,1-bis(4-methoxyphenyl)-1′-pyrenylmethyl, 9-anthryl,9-(9-phenyl)xanthenyl, 9-(9-phenyl-10-oxo)anthryl,1,3-benzodithiolan-2-yl, and benzisothiazolyl S,S-dioxido.

Silyl Ethers

Examples of silyl ethers include trimethylsilyl, triethylsilyl,triisopropylsilyl, dimethylisopropylsilyl, diethylisopropylsilyl,dimethylthexylsilyl, t-butyldimethylsilyl, t-butyldiphenylsilyl,tribenzylsilyl, tri-p-xylylsilyl, triphenylsilyl, diphenylmethylsilyl,and t-butylmethoxyphenylsilyl.

Esters

In addition to ethers, a hydroxyl group may be protected as an ester.Examples of esters include formate, benzoylformate, acetate,chloroacetate, dichloroacetate, trichloroacetate, trifluoroacetate,methoxyacetate, tri phenylmethoxyacetate, phenoxyacetate,p-chlorophenoxyacetate, p-P-phenylacetate, 3-phenylpropionate,4-oxopentanoate(levulinate), 4,4-(ethylenedithio)pentanoate, pivaloate,adamantoate, crotonate, 4-methoxycrotonate, benzoate, p-phenylbenzoate,2,4,6-trimethylbenzoate(mesitoate)

Carbonates

Examples of carbonates include methyl, 9-fluorenylmethyl, ethyl,2,2,2-trichloroethyl, 2-(trimethylsilyl)ethyl, 2-(phenylsulfonyl)ethyl,2-(triphenylphosphonio)ethyl, isobutyl, vinyl, allyl, p-nitrophenyl,benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, o-nitrobenzyl,p-nitrobenzyl, S-benzyl thiocarbonate, 4-ethoxy-1-naphthyl, and methyldithiocarbonate.

Assisted Cleavage

Examples of assisted cleavage include 2-iodobenzoate, 4-azidobutyrate,4-nitro-4-methylpentanoate, o-(dibromomethyl)benzoate,2-formylbenzenesulfonate, 2-(methylthiomethoxy)ethyl carbonate,4-(methylthiomethoxy)butyrate, and 2-(methylthiomethoxymethyl)benzoate.

Miscellaneous Esters

Examples of miscellaneous esters include2,6-dichloro-4-methylphenoxyacetate,2,6-dichloro-4-(1,1,3,3-tetramethylbutyl)phenoxyacetate,2,4-bis(1,1-dimethylpropyl)phenoxyacetate, chlorodiphenylacetate,isobutyrate, monosuccinoate, (E)-2-methyl-2-butenoate(tigloate),o-(methoxycarbonyl)benzoate, p-P-benzoate, α-naphthoate, nitrate, alkylN,N,N′,N′-tetramethylphosphorodiamidate, N-phenylcarbamate, borate,dimethylphosphinothioyl, and 2,4-dinitrophenylsulfenate

Sulfonates

Examples of sulfonates include sulfate, methanesulfonate(mesylate),benzylsulfonate, and tosylate.

Protection for 1,2- and 1,3-diols

Cyclic Acetals and Ketals

Examples of cyclic acetals and ketals include methylene, ethylidene,1-t-butylethylidene, 1-phenylethylidene, (4-methoxyphenyl)ethylidene,2,2,2-trichloroethylidene, acetonide (isopropylidene), cyclopentylidene,cyclohexylidene, cycloheptylidene, benzylidene, p-methoxybenzylidene,2,4-dimethoxybenzylidene, 3,4-dimethoxybenzylidene, and2-nitrobenzylidene.

Cyclic Ortho Esters

Examples of cyclic ortho esters include methoxymethylene,ethoxymethylene, dimethoxymethylene, 1-methoxyethylidene,1-ethoxyethylidine, 1,2-dimethoxyethylidene, α-methoxybenzylidene,1-(N,N-dimethylamino)ethylidene derivative,α-(N,N-dimethylamino)benzylidene derivative, and 2-oxacyclopentylidene.

Silyl Derivatives

Examples of silyl derivatives include di-t-butylsilylene group, and1,3-(1,1,3,3-tetraisopropyldisiloxanylidene) derivative.

Amino Protecting Groups

Protection for the amino group includes carbamates, amides, and special—NH protective groups.

Examples of carbamates include methyl and ethyl carbamates, substitutedethyl carbamates, assisted cleavage carbamates, photolytic cleavagecarbamates, urea-type derivatives, and miscellaneous carbamates.

Carbamates

Examples of methyl and ethyl carbamates include methyl and ethyl,9-fluorenylmethyl, 9-(2-sulfo)fluorenylmethyl,9-(2,7-dibromo)fluorenylmethyl,2,7-di-t-butyl-{9-(10,10-dioxo-10,10,10,10-tetrahydrothioxanthyl)}methyl,and 4-methoxyphenacyl.

Substituted Ethyl

Examples of substituted ethyl carbamates include 2,2,2-trichloroethyl,2-trimethylsilylethyl, 2-phenylethyl, 1-(1-adamantyl)-1-methylethyl,1,1-dimethyl-2-haloethyl, 1,1-dimethyl-2,2-dibromoethyl,1,1-dimethyl-2,2,2-trichloroethyl, 1-methyl-1-(4-biphenylyl)ethyl,1-(3,5-di-t-butylphenyl)-1-methylethyl, 2-(2′- and 4′-pyridyl)ethyl,2-(N,N-dicyclohexylcarboxamido)ethyl, t-butyl, 1-adamantyl, vinyl,allyl, 1-isopropylallyl, cinnamyl, 4-nitrocinnamyl, 8-quinolyl,N-hydroxypiperidinyl, alkyldithio, benzyl, p-methoxybenzyl,p-nitrobenzyl, p-bromobenzyl, p-chlorobenzyl, 2,4-dichlorobenzyl,4-methylsulfinylbenzyl, 9-anthrylmethyl and diphenylmethyl.

Assisted Cleavage

Examples of assisted cleavage include 2-methylthioethyl,2-methylsulfonylethyl, 2-(p-toluenesulfonyl)ethyl,{2-(1,3-dithianyl)}methyl, 4-methylthiophenyl, 2,4-dimethylthiophenyl,2-phosphonioethyl, 2-triphenylphosphonioisopropyl,1,1-dimethyl-2-cyanoethyl, m-chloro-p-acyloxybenzyl,p-(dihydroxyboryl)benzyl, 5-benzisoxazolylmethyl, and2-(trifluoromethyl)-6-chromonylmethyl.

Photolytic Cleavage

Examples of photolytic cleavage include m-nitrophenyl,3,5-dimethoxybenzyl, o-nitrobenzyl, 3,4-dimethoxy-6-nitrobenzyl, andphenyl(o-nitrophenyl)methyl.

Urea-Type Derivatives

Examples of urea-type derivatives include phenothiazinyl-(10)-carbonylderivative, N′-p-toluenesulfonylaminocarbonyl, andN′-phenylaminothiocarbonyl.

Miscellaneous Carbamates

Examples of miscellaneous carbamates include t-amyl, S-benzylthiocarbamate, p-cyanobenzyl, cyclobutyl, cyclohexyl, cyclopentyl,cyclopropylmethyl, p-decyloxybenzyl, diisopropylmethyl,2,2-dimethoxycarbonylvinyl, o-(N,N-dimethylcarboxamido)benzyl,1,1-dimethyl-3-(N,N-dimethylcarboxamido)propyl, 1,1-dimethylpropynyl,di(2-pyridyl)methyl, 2-furanylmethyl, 2-iodoethyl, isobornyl, isobutyl,isonicotinyl, p-(p′-methoxyphenylazo)benzyl, 1-methylcyclobutyl,1-methylcyclohexyl, 1-methyl-1-cyclopropylmethyl,1-methyl-1-(3,5-dimethoxyphenyl)ethyl,1-methyl-1-(p-phenylazophenyl)ethyl, 1-methyl-1-phenylethyl,1-methyl-1-(4-pyridyl)ethyl, phenyl, p-(phenylazo)benzyl,2,4,6-tri-t-butylphenyl, 4-(trimethylammonium)benzyl, and2,4,6-trimethylbenzyl.

Examples of amides include:

Amides

N-formyl, N-acetyl, N-chloroacetyl, N-trichloroacetyl,N-trifluoroacetyl, N-phenylacetyl, N-3-phenylpropionyl, N-picolinoyl,N-3-pyridylcarboxamide, N-benzoylphenylalanyl derivative, N-benzoyl,N-p-phenylbenzoyl.

Assisted Cleavage

N-o-nitrophenylacetyl, N-o-nitrophenoxyacetyl, N-acetoacetyl,(N′-dithiobenzyloxycarbonylamino)acetyl, N-3-(p-hydroxyphenyl)propionyl,N-3-(o-nitrophenyl)propionyl, N-2-methyl-2-(o-nitrophenoxy)propionyl,N-2-methyl-2-(o-phenylazophenoxy)propionyl, N-4-chlorobutyryl,N-3-methyl-3-nitrobutyryl, N-o-nitrocinnamoyl, N-acetylmethioninederivative, N-o-nitrobenzoyl, N-o-(benzoyloxymethyl)benzoyl, and4,5-diphenyl-3-oxazolin-2-one.

Cyclic Imide Derivatives

N-phthalimide, N-dithiasuccinoyl, N-2,3-diphenylmaleoyl,N-2,5-dimethylpyrrolyl, N-1,1,4,4-tetramethyldisilylazacyclopentaneadduct, 5-substituted 1,3-dimethyl-1,3,5-triazacyclohexan-2-one,5-substituted 1,3-dibenzyl-1,3,5-triazacyclohexan-2-one, and1-substituted 3,5-dinitro-4-pyridonyl.

Special—NH Protective Groups

Examples of special NH protective groups include:

N-Alkyl and N-Aryl Amines

N-methyl, N-allyl, N-{2-(trimethylsilyl)ethoxy}methyl,N-3-acetoxypropyl, N-(1-isopropyl-4-nitro-2-oxo-3-pyrrolin-3-yl),quaternary ammonium salts, N-benzyl, N-4-methoxybenzyl,N-di(4-methoxyphenyl)methyl, N-5-dibenzosuberyl, N-triphenylmethyl,N-(4-methoxyphenyl)diphenylmethyl, N-9-phenylfluorenyl,N-2,7-dichloro-9-fluorenylmethylene, N-ferrocenylmethyl, andN-2-picolylamine N′-oxide.

Imine Derivatives

N-1,1-dimethylthiomethylene, N-benzylidene, N-p-methoxybenzylidene,N-diphenylmethylene, N-{(2-pyridyl)mesityl}methylene, andN-(N′,N′-dimethylaminomethylene).

Protection for the Carbonyl Group

Acyclic Acetals and Ketals

Examples of acyclic acetals and ketals include dimethyl,bis(2,2,2-trichloroethyl), dibenzyl, bis(2-nitrobenzyl) and diacetyl.

Cyclic Acetals and Ketals

Examples of cyclic acetals and ketals include 1,3-dioxanes,5-methylene-1,3-dioxane, 5,5-dibromo-1,3-dioxane,5-(2-pyridyl)-1,3-dioxane, 1,3-dioxolanes, 4-bromomethyl-1,3-dioxolane,4-(3-butenyl)-1,3-dioxolane, 4-phenyl-1,3-dioxolane,4-(2-nitrophenyl)-1,3-dioxolane, 4,5-dimethoxymethyl-1,3-dioxolane,O,O′-phenylenedioxy and 1,5-dihydro-3H-2,4-benzodioxepin.

Acyclic Dithio Acetals and Ketals

Examples of acyclic dithio acetals and ketals include S,S′-dimethyl,S,S′diethyl, S,S′-dipropyl, S,S′-dibutyl, S,S′-dipentyl, S,S′-diphenyl,S,S′-dibenzyl and S,S′-diacetyl.

Cyclic Dithio Acetals and Ketals

Examples of cyclic dithio acetals and ketals include 1,3-dithiane,1,3-dithiolane and 1,5-dihydro-3H-2,4-benzodithiepin.

Acyclic Monothio Acetals and Ketals

Examples of acyclic monothio acetals and ketals includeO-trimethylsilyl-S-alkyl, O-methyl-5-alkyl or —S-phenyl andO-methyl-S-2-(methylthio)ethyl.

Cyclic Monothio Acetals and Ketals

Examples of cyclic monothio acetals and ketals include 1,3-oxathiolanes.

Miscellaneous Derivatives

O-Substituted Cyanohydrins

Examples of O-substituted cyanohydrins include O-acetyl,O-trimethylsilyl, O-1-ethoxyethyl and O-tetrahydropyranyl.

Substituted Hydrazones

Examples of substituted hydrazones include N,N-dimethyl and2,4-dinitrophenyl.

Oxime Derivatives

Examples of oxime derivatives include O-methyl, O-benzyl andO-phenylthiomethyl.

Imines

Substituted Methylene Derivatives, Cyclic Derivatives

Examples of substituted methylene and cyclic derivatives includeoxazolidines, 1-methyl-2-(1′-hydroxyalkyl)imidazoles,N,N′-dimethylimidazolidines, 2,3-dihydro-1,3-benzothiazoles,diethylamine adducts, and methylaluminumbis(2,6-di-t-butyl-4-methylphenoxide)(MAD)complex.

Monoprotection of Dicarbonyl Compounds

Selective Protection of α- and β-Diketones

Examples of selective protection of α- and β-diketones include enamines,enol acetates, enol ethers, methyl, ethyl, i-butyl, piperidinyl,morpholinyl, 4-methyl-1,3-dioxolanyl, pyrrolidinyl, benzyl, S-butyl, andtrimethylsilyl.

Cyclic Ketals, Monothio and Dithio Ketals

Examples of cyclic ketals, monothio and dithio ketals includebismethylenedioxy derivatives and tetramethylbismethylenedioxyderivatives.

Protection for the Carboxyl Group

Esters

Substituted Methyl Esters

Examples of substituted methyl esters include 9-fluorenylmethyl,methoxymethyl, methylthiomethyl, tetrahydropyranyl, tetrahydrofuranyl,methoxyethoxymethyl, 2-(trimethylsilyl)ethoxymethyl, benzyloxymethyl,phenacyl, p-bromophenacyl, α-methylphenacyl, p-methoxyphenacyl,carboxamidomethyl, and N-phthalimidomethyl.

2-Substituted Ethyl Esters

Examples of 2-substituted ethyl esters include 2,2,2-trichloroethyl,

2-haloethyl, ω-chloroalkyl, 2-(trimethylsilyl)ethyl, 2-methylthioethyl,1,3-dithianyl-2-methyl, 2-(p-nitrophenylsulfenyl)ethyl,2-(p-toluenesulfonyl)ethyl,

2-(2′-pyridyl)ethyl, 2-(diphenylphosphino)ethyl, 1-methyl-1-phenylethyl,t-butyl, cyclopentyl, cyclohexyl, allyl, 3-buten-1-yl,4-(trimethylsilyl)-2-buten-1-yl, cinnamyl, α-methylcinnamyl, phenyl,p-(methylmercapto)phenyl and benzyl.

Substituted Benzyl Esters

Examples of substituted benzyl esters include triphenylmethyl,diphenylmethyl, bis(o-nitrophenyl)methyl, 9-anthrylmethyl,2-(9,10-dioxo)anthrylmethyl, 5-dibenzosuberyl, 1-pyrenylmethyl,2-(trifluoromethyl)-6-chromylmethyl, 2,4,6-trimethylbenzyl,p-bromobenzyl, o-nitrobenzyl, p-nitrobenzyl, p-methoxybenzyl,2,6-dimethoxybenzyl, 4-(methylsulfinyl)benzyl, 4-sulfobenzyl, piperonyl,4-picolyl and p-P-benzyl.

Silyl Esters

Examples of silyl esters include trimethylsilyl, triethylsilyl,t-butyldimethylsilyl, i-propyldimethylsilyl, phenyldimethylsilyl anddi-t-butylmethylsilyl.

Activated Esters

Examples of activated esters include thiols.

Miscellaneous Derivatives

Examples of miscellaneous derivatives include oxazoles,2-alkyl-1,3-oxazolines, 4-alkyl-5-oxo-1,3-oxazolidines,5-alkyl-4-oxo-1,3-dioxolanes, ortho esters, phenyl group andpentaminocobalt(III) complex.

Stannyl Esters

Examples of stannyl esters include triethylstannyl andtri-n-butylstannyl.

Amides and Hydrazides

Amides

Examples of amides include N,N-dimethyl, pyrrolidinyl, piperidinyl,5,6-dihydrophenanthridinyl, o-nitroanilides, N-7-nitroindolyl,N-8-Nitro-1,2,3,4-tetrahydroquinolyl, and p-P-benzenesulfonamides.

Hydrazides

Examples of hydrazides include N-phenyl and N,N′-diisopropyl.

The compounds of the invention can be prepared according to the methodsdescribed in the next section.

C. SYNTHESIS

The compounds of the invention can be prepared according to traditionalsynthetic organic methods and matrix or combinatorial chemistry methods,as shown in Scheme 1 below and in Examples 1-72. A person of ordinaryskill will be aware of variations and adaptations of the schemes andexamples provided to achieve the compounds of the invention.

One skilled in the art will recognize that synthesis of the compounds ofthe present invention may be effected by purchasing intermediate orprotected intermediate compounds described in any of the Schemesdisclosed herein. Throughout the schemes when the reacting functionalityis located at R⁴, one skilled in the art will recognize that the choiceof R⁴ is illustrative only and that the reacting functionality couldalso be located at R³ or R² also.

One skilled in the art will further recognize that during any of theprocesses for preparation of the compounds of the present invention, itmay be necessary and/or desirable to protect sensitive or reactivegroups on any of the molecules concerned. This may be achieved by meansof conventional protecting groups, such as those described in“Protective Groups in Organic Chemistry”, ed. J. F. W. McOmie, PlenumPress, 1973; and T. W. Greene & P. G. M. Wuts, “Protective Groups inOrganic Synthesis”, John Wiley & Sons, 1991. The protecting groups maybe removed at a convenient subsequent stage using methods known from theart.

Compounds of formula (XIII) may be prepared according to the processesoutlined in Scheme 1. One skilled in the art will recognize that thelocation of formyl functionality at R⁴ is for illustrative purposes onlyand that the formyl group may also be located at R² or R³.

A compound of formula (XIII) is prepared as outlined in Scheme 1 from acompound of formula (V), in which the group M¹ represents anitrogen-protecting group. One skilled in the art will be capable ofselecting a protecting group that is compatible with the transformationsin Scheme 1. In a particularly preferred embodiment, the group M¹ istert-butyl-carbamoyl. A compound of formula (VI) is obtained from acompound of formula (V) by reacting a compound of formula (V) with analdehyde or ketone under reductive amination conditions in the presenceof a reductant such as sodium triacetoxyborohydride, sodiumcyanoborohydride, or phenylsilane in a solvent such as THF, DCE, DCM,methanol, ethanol, or ether at a temperature between 0 and 80° C. Oneskilled in the art will recognize that the use of a promotor or catalystwith acidic character such as organometallic complexes or carboxylicacids may increase the rate of the reaction and/or reduce the formationof by-products. In a particularly preferred embodiment, a compound offormula (V) is reacted with an aldehyde or ketone, acetic acid, andsodium triacetoxyborohydride in DCE at room temperature. A compound offormula (VII) is obtained from a compound of formula (VI) by reacting acompound of formula (VI) with a reagent capable of removing theprotecting group M¹ under nitrogen-deprotection conditions. In apreferred embodiment a compound of formula (VI), in which the protectinggroup M¹ is tert-butyl carbamoyl, is reacted with an acid such asanhydrous hydrogen chloride in a solvent such as dioxane or ether atroom temperature. A compound of formula (IX) is obtained by reacting acompound of formula (VII) with a compound of formula (VIII) underamide-formation conditions. In a preferred embodiment, a compound offormula (VII), either as a free base or as a mineral acid salt, isreacted with a compound of formula (VIII) in the presence of adehydrating agent and a base in a solvent at a temperature between 0° C.and 60° C. In a particularly preferred embodiment, a compound of formula(VII) as a hydrochloride salt is used, the dehydrating agent is1-{3-(dimethylamino)propyl}-3-ethylcarbodiimide hydrochloride and1-hydroxybenzotriazole hydrate, and the base is N-methylmorpholine. Acompound of formula (XIII) is obtained by reacting a compound of formula(IX) with a compound of formula (XI) in the presence of a reducing agentunder reductive amination conditions, as outlined in step A. A compoundof formula (X) is obtained by reacting a compound of formula (V) with acompound of formula (VIII) under amide formation conditions as outlinedin step C. A compound of formula (XII) is obtained by reacting acompound of formula (X) with a compound of formula (XI) under reductiveamination conditions, as described in step A. A compound of formula(XIV) is obtained by reacting a compound of formula (XII) with a reagentcapable of removing the protecting group M¹ under nitrogen-deprotectionconditions, as outlined in step B. A compound of formula (XIII) isobtained by reacting a compound of formula (XIV) with an aldehyde orketone under reductive amination conditions as outlined in step A.Compounds of the present invention may also be conveniently preparedusing various other chemical intermediates. For example, variants ofaldehyde (VIII) or amide (IX) could be accessed from a correspondingaryl halide, such as an aryl bromide, via a palladium mediated couplingwith a formyl, carbonyl, or nitrile equivalent.

D. FORMULATION, ADMINISTRATION, AND THERAPY

The disclosed compounds, alone or in combination (with, for example, ahistamine H₁ receptor antagonist), are useful for treating or preventingneurologic disorders including sleep/wake and arousal/vigilancedisorders (e.g. insomnia and jet lag), attention deficit hyperactivitydisorders (ADHD), learning and memory disorders, cognitive dysfunction,migraine, neurogenic inflammation, dementia, mild cognitive impairment(pre-dementia), Alzheimer's disease, epilepsy, narcolepsy, eatingdisorders, obesity, motion sickness, vertigo, schizophrenia, substanceabuse, bipolar disorders, manic disorders and depression, as well asother histamine H₃ receptor mediated disorders such as upper airwayallergic response, asthma, itch, nasal congestion and allergic rhinitisin a subject in need thereof.

1. Formulation and Administration

The compounds or compositions of the invention may be formulated andadministered to a subject by any conventional route of administration,including, but not limited to, intravenous, oral, subcutaneous,intramuscular, intradermal and parenteral administration. The quantityof the compound which is effective for treating each condition may vary,and can be determined by one of ordinary skill in the art.

For use in medicine, the salts of the compounds of this invention referto non-toxic “pharmaceutically acceptable salts.” Other salts may,however, be useful in the preparation of compounds according to thisinvention or of their pharmaceutically acceptable salts. Suitablepharmaceutically acceptable salts of the compounds include acid additionsalts that may, for example, be formed by mixing a solution of thecompound with a solution of a pharmaceutically acceptable acid such ashydrochloric acid, sulfuric acid, fumaric acid, maleic acid, succinicacid, acetic acid, benzoic acid, citric acid, tartaric acid, carbonicacid or phosphoric acid. Furthermore, where the compounds of theinvention carry an acidic moiety, suitable pharmaceutically acceptablesalts thereof may include alkali metal salts, e.g., sodium or potassiumsalts; alkaline earth metal salts, e.g., calcium or magnesium salts; andsalts formed with suitable organic ligands, e.g., quaternary ammoniumsalts.

Thus, representative pharmaceutically acceptable salts include thefollowing: acetate, benzenesulfonate, benzoate, bicarbonate, bisulfate,bitartrate, borate, bromide, calcium edetate, camsylate, carbonate,chloride, clavulanate, citrate, dihydrochloride, edetate, edisylate,estolate, esylate, fumarate, gluceptate, gluconate, glutamate,glycollylarsanilate, hexylresorcinate, hydrabamine, hydrobromide,hydrochloride, hydroxynaphthoate, iodide, isothionate, lactate,lactobionate, laurate, malate, maleate, mandelate, mesylate,methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate,N-methylglucamine ammonium salt, oleate, pamoate (embonate), palmitate,pantothenate, phosphate/diphosphate, polygalacturonate, salicylate,stearate, sulfate, subacetate, succinate, tannate, tartrate, teoclate,tosylate, triethiodide and valerate.

The present invention includes within its scope prodrugs of thecompounds of this invention. In general, such prodrugs will befunctional derivatives of the compounds that are readily convertible invivo into the required compound. Thus, in the methods of treatment ofthe present invention, the term “administering” shall encompass thetreatment of the various disorders described with the compoundspecifically disclosed or with a compound that may not be specificallydisclosed, but which converts to the specified compound in vivo afteradministration to the patient. Conventional procedures for the selectionand preparation of suitable prodrug derivatives are described, forexample, in “Design of Prodrugs”, ed. H. Bundgaard, Elsevier, 1985. Inaddition to salts, the invention provides the esters, amides, and otherprotected or derivatized forms of the described compounds.

Where the compounds according to this invention have at least one chiralcenter, they may accordingly exist as enantiomers. Where the compoundspossess two or more chiral centers, they may additionally exist asdiastereomers. It is to be understood that all such isomers and mixturesthereof are encompassed within the scope of the present invention.Furthermore, some of the crystalline forms for the compounds may existas polymorphs and as such are intended to be included in the presentinvention. In addition, some of the compounds may form solvates withwater (i.e., hydrates) or common organic solvents, and such solvates arealso intended to be encompassed within the scope of this invention.

The present invention also provides pharmaceutical compositionscomprising one or more compounds of this invention in association with apharmaceutically acceptable carrier and optionally additionalpharmaceutical agents such as H₁ antagonists or SSRIs. Preferably thesecompositions are in unit dosage forms such as pills, tablets, caplets,capsules (each including immediate release, timed release and sustainedrelease formulations), powders, granules, sterile parenteral solutionsor suspensions (including syrups and emulsions), metered aerosol orliquid sprays, drops, ampoules, autoinjector devices or suppositories;for oral, parenteral, intranasal, sublingual or rectal administration,or for administration by inhalation or insufflation. Alternatively, thecomposition may be presented in a form suitable for once-weekly oronce-monthly administration; for example, an insoluble salt of theactive compound, such as the decanoate salt, may be adapted to provide adepot preparation for intramuscular injection. For preparing solidcompositions such as tablets, the principal active ingredient is mixedwith a pharmaceutical carrier, e.g. conventional tableting ingredientssuch as corn starch, lactose, sucrose, sorbitol, talc, stearic acid,magnesium stearate, dicalcium phosphate or gums, and otherpharmaceutical diluents, e.g. water, to form a solid pre-formulationcomposition containing a homogeneous mixture of a compound of thepresent invention, or a pharmaceutically acceptable salt thereof. Whenreferring to these pre-formulation compositions as homogeneous, it ismeant that the active ingredient is dispersed evenly throughout thecomposition so that the composition may be readily subdivided intoequally effective dosage forms such as tablets, pills and capsules. Thissolid pre-formulation composition is then subdivided into unit dosageforms of the type described above containing from 5 to about 1000 mg ofthe active ingredient of the present invention. Examples include 5 mg, 7mg, 10 mg, 15 mg, 20 mg, 35 mg, 50 mg, 75 mg, 100 mg, 120 mg, 150 mg,and so on. The tablets or pills of the disclosed compositions can becoated or otherwise compounded to provide a dosage form affording theadvantage of prolonged action. For example, the tablet or pill cancomprise an inner dosage and an outer dosage component, the latter beingin the form of an envelope over the former. The two components can beseparated by an enteric layer, which serves to resist disintegration inthe stomach and permits the inner component to pass intact into theduodenum or to be delayed in release. A variety of material can be usedfor such enteric layers or coatings, such materials including a numberof polymeric acids with such materials as shellac, cetyl alcohol andcellulose acetate.

The liquid forms in which the compounds and compositions of the presentinvention may be incorporated for administration orally or by injectioninclude, aqueous solutions, suitably flavored syrups, aqueous or oilsuspensions, and flavored emulsions with edible oils such as cottonseedoil, sesame oil, coconut oil or peanut oil, as well as elixirs andsimilar pharmaceutical vehicles. Suitable dispersing or suspendingagents for aqueous suspensions, include synthetic and natural gums suchas tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose,methylcellulose, polyvinyl-pyrrolidone or gelatin.

Where the processes for the preparation of the compounds according tothe invention give rise to mixture of stereoisomers, these isomers maybe separated by conventional techniques such as preparativechromatography. The compounds may be prepared in racemic form, orindividual enantiomers may be prepared either by enantiospecificsynthesis or by resolution. The compounds may, for example, be resolvedinto their component enantiomers by standard techniques, such as theformation of diastereomeric pairs by salt formation with an opticallyactive acid, such as (−)-di-p-toluoyl-d-tartaric acid and/or(+)-di-p-toluoyl-l-tartaric acid followed by fractional crystallizationand regeneration of the free base. The compounds may also be resolved byformation of diastereomeric esters or amides, followed bychromatographic separation and removal of the chiral auxiliary.Alternatively, the compounds may be resolved using a chiral HPLC column.

Advantageously, compounds of the present invention may be administeredin a single daily dose, or the total daily dosage may be administered individed doses of two, three or four times daily. Furthermore, compoundsfor the present invention can be administered in intranasal form viatopical use of suitable intranasal vehicles, or via transdermal skinpatches well known to those of ordinary skill in that art. To beadministered in the form of a transdermal delivery system, the dosageadministration will, of course, be continuous rather than intermittentthroughout the dosage regimen.

For instance, for oral administration in the form of a tablet orcapsule, the active drug component can be combined with an oral,non-toxic pharmaceutically acceptable inert carrier such as ethanol,glycerol, water and the like. Moreover, when desired or necessary,suitable binders, lubricants, disintegrating agents and coloring agentscan also be incorporated into the mixture. Suitable binders include,without limitation, starch, gelatin, natural sugars such as glucose orbeta-lactose, corn sweeteners, natural and synthetic gums such asacacia, tragacanth or sodium oleate, sodium stearate, magnesiumstearate, sodium benzoate, sodium acetate, sodium chloride and the like.Disintegrators include, without limitation, starch, methyl cellulose,agar, bentonite, xanthan gum and the like.

The compound of the present invention can also be administered in theform of liposome delivery systems, such as small unilamellar vesicles,large unilamellar vesicles, and multilamellar vesicles. Liposomes can beformed from a variety of phospholipids, such as cholesterol,stearylamine or phophatidylcholines.

Compounds of the present invention may also be delivered by the use ofmonoclonal antibodies as individual carriers to which the compoundmolecules are coupled. The compounds of the present invention may alsobe coupled with soluble polymers as targetable drug carriers. Suchpolymers can include polyvinylpyrrolidone, pyran copolymer,polyhydroxypropylmethacrylamidephenol,polyhydroxyethylaspartamidephenol, or polyethyleneoxidepolylysinesubstituted with palmitoyl residue. Furthermore, the compounds of thepresent invention may be coupled to a class of biodegradable polymersuseful in achieving controlled release of a drug, for example,polylactic acid, polyepsilon caprolactone, polyhydroxy butyric acid,polyoesters, polyacetals, polydihydropyrans, polycyanoacrylates andcross-linked or amphipathic block copolymers of hydrogels.

Compounds of this invention may be administered in any of the foregoingcompositions and according to dosage regimens established in the artwhenever treatment is required.

The daily dosage of the products may be varied over a wide range from 1to 1,000 mg per adult human per day. For oral administration, thecompositions are preferably provided in the form of tablets containing1.0, 5.0, 10.0, 15.0, 25.0, 50.0, 100, 250 and 500 milligrams of theactive ingredient for the symptomatic adjustment of the dosage to thesubject to be treated. An effective amount of the drug is ordinarilysupplied at a dosage level of from about 0.01 mg/kg to about 20 mg/kg ofbody weight per day. Preferably, the range is from about 0.02 mg/kg toabout 10 mg/kg of body weight per day, and especially from about 0.05mg/kg to about 10 mg/kg of body weight per day. The compounds may beadministered on a regimen of 1 to 4 times per day.

Optimal dosages to be administered may be readily determined by thoseskilled in the art, and will vary with the particular compound used, themode of administration, the strength of the preparation, the mode ofadministration, and the advancement of the disease condition. Inaddition, factors associated with the particular patient being treated,including patient age, weight, diet and time of administration, willresult in the need to adjust dosages.

2. Combination Therapy

The disclosed compounds are useful in combination with other therapeuticagents, including H₁ receptor antagonists, H₂ receptor antagonists, andneurotransmitter modulators such as SSRIs and non-selective serotoninre-uptake inhibitors (NSSRIs).

Methods are known in the art for determining effective doses fortherapeutic and prophylactic purposes for the disclosed pharmaceuticalcompositions or the disclosed drug combinations, whether or notformulated in the same composition. For therapeutic purposes, the term“jointly effective amount” as used herein, means that amount of eachactive compound or pharmaceutical agent, alone or in combination, thatelicits the biological or medicinal response in a tissue system, animalor human that is being sought by a researcher, veterinarian, medicaldoctor or other clinician, which includes alleviation of the symptoms ofthe disease or disorder being treated. For prophylactic purposes (i.e.,inhibiting the onset or progression of a disorder), the term “jointlyeffective amount” refers to that amount of each active compound orpharmaceutical agent, alone or in combination, that inhibits in asubject the onset or progression of a disorder as being sought by aresearcher, veterinarian, medical doctor or other clinician, thedelaying of which disorder is mediated, at least in part, by themodulation of one or more histamine receptors. Thus, the presentinvention provides combinations of two or more drugs wherein, forexample, (a) each drug is administered in an independentlytherapeutically or prophylactically effective amount; (b) at least onedrug in the combination is administered in an amount that issub-therapeutic or sub-prophylactic if administered alone, but istherapeutic or prophylactic when administered in combination with thesecond or additional drugs according to the invention; or (c) both drugsare administered in an amount that is sub-therapeutic orsub-prophylactic if administered alone, but are therapeutic orprophylactic when administered together. Combinations of three or moredrugs are analogously possible. Methods of combination therapy includeco-administration of a single formulation containing all active agents;essentially contemporaneous administration of more than one formulation;and administration of two or more active agents separately formulated.

E. EXAMPLES

In order to illustrate the invention, the following examples areincluded. These examples do not limit the invention. They are only meantto suggest a method of practicing the invention. Those skilled in theart may find other methods of practicing the invention, which areobvious to them. However, those methods are deemed to be within thescope of this invention. Protocol for Preparative Reversed-Phase HPLCGilson ® Column: YMC-Pack ODS-A, 5 μm, 75 × 30 mm Flow rate: 25 mL/minDetection: λ = 220 & 254 nm Gradient (acetonitrile/water, 0.05%trifluoroacetic acid) 1) 0.0 min 15% acetonitrile/85% water 2) 20.0 min99% acetonitrile/1% water Protocol for HPLC (Reversed-Phase) HewlettPackard Series 1100 Column: Agilent ZORBAX ® Bonus RP, 5 μm, 4.6 × 250mm Flow rate: 1 mL/min Detection: λ = 220 & 254 nm Gradient(acetonitrile/water, 0.05% trifluoroacetic acid) 1) 0.0 min 1%acetonitrile/99% water 2) 20.0 min 99% acetonitrile/1% water

Mass spectra were obtained on an Agilent series 1100 MSD usingelectrospray ionization (ESI) in either positive or negative modes asindicated.

Thin-layer chromatography was performed using Merck silica gel 60 F₂₅₄2.5 cm×7.5 cm 250 μm or 5.0 cm×10.0 cm 250 μm pre-coated silica gelplates. Preparative thin-layer chromatography was performed using EMScience silica gel 60 F₂₅₄ 20 cm×20 cm 0.5 mm pre-coated plates with a20 cm×4 cm concentrating zone.

NMR spectra were obtained on either a Bruker model DPX400 (400 MHz) orDPX500 (500 MHz) spectrometer. The format of the ¹H NMR data below is:chemical shift in ppm down field of the tetramethylsilane reference(multiplicity, coupling constant J in Hz, integration).

Example 1

4-sec-Butyl-piperazine-1-carboxylic acid tert-butyl ester

A mixture of piperazine-1-carboxylic acid tert-butyl ester (7.00 g),3-pentanone (3.89 g), glacial acetic acid (2.22 mL) and sodiumtriacetoxyborohydride (11.95 g) in dichloromethane (DCM, 200 mL) wasstirred for 18 h at room temperature. The reaction mixture was quenchedwith 1 N aqueous NaOH (80 mL) and stirred for 2.5 h at room temperature.Additional water (100 mL) was added, and the resulting mixture wasextracted with DCM (3×100 mL). Extracts were combined and washed withwater (2×100 mL), dried (Na₂SO₄), and concentrated under reducedpressure, yielding the title compound (6.28 g).

The products of Example 2 through Example 5 were prepared in analogywith the procedure of Example 1 using the specified carbonyl compoundand amine.

Example 2

4-(1-Ethyl-propyl)-piperazine-1-carboxylic acid tert-butyl ester

Prepared from 3-pentanone and piperazine-1-carboxylic acid tert-butylester.

Example 3

4-Butyl-piperazine-1-carboxylic acid tert-butyl ester

Prepared from butanal and piperazine-1-carboxylic acid tert-butyl ester.

Example 4

4-(1-Methyl-heptyl)-piperazine-1-carboxylic acid tert-butyl ester

Prepared from 2-octanone and piperazine-1-carboxylic acid tert-butylester.

Example 5

4-Isopropyl-piperazine-1-carboxylic acid tert-butyl ester

Prepared from acetone and piperazine-1-carboxylic acid tert-butyl ester.

Example 6

1-sec-Butyl-piperazine dihydrochloride

To a solution of the product of Example 1 (6.28 g) in methanol (120 mL)at 5° C. was added 4 M HCl in dioxane (100 mL). The reaction mixture wasstirred at room temperature. After 24 h, the solvent was evaporatedunder vacuum. Ethyl ether was added and evaporated to dryness undervacuum (2×100 mL). The resulting white solid was dried under vacuum for24 h yielding the title compound as its dihydrochloride salt (4.93 g) asa white solid.

The products of Example 7 through Example 10 were prepared in analogy tothe procedure of Example 6 from the specified tert-butylcarbamate.

Example 7

1-(1-Ethyl-propyl)-piperazine dihydrochloride

Prepared from the product of Example 2.

Example 8

1-Butyl-piperazine dihydrochloride

Prepared from the product of Example 3.

Example 9

1-(1-Methyl-heptyl)-piperazine dihydrochloride

Prepared from the product of Example 4.

Example 10

1-Isopropyl-piperazine dihydrochloride

Prepared from the product of Example 5.

Example 11

4-(4-sec-Butyl-piperazine-1-carbonyl)-benzaldehyde

The product of Example 6 (3.2 g) and 4-formylbenzoic acid (2.102 g) weresuspended in DCM (130 mL) under nitrogen.1-{3-(Dimethylamino)propyl}-3-ethylcarbodiimide hydrochloride (3.96 g),1-hydroxybenzotriazole hydrate (3.06 g) and N-methylmorpholine (9.432 g)were added in sequence to the above suspension. The reaction mixture wasstirred under nitrogen for 24 h. DCM (100 mL) was added, the resultingmixture was washed with 10% aqueous NaOH solution (2×50 mL) and water(2×100 mL), and the separated organic phase was dried over anhydrousMgSO₄, and concentrated under reduced pressure to yield the crudeproduct (3.75 g). Chromatography of the residue on silica gel (2-5% 2 Mmethanolic ammonia/DCM) yielded the title compound (2.75 g).

The products of Example 12 through Example 18 were prepared in analogyto the procedure of Example 11 using the specified piperazinederivatives and carboxylic acids.

Example 12

4-{4-(1-Ethyl-propyl)-piperazine-1-carbonyl}-benzaldehyde

Prepared from the product of Example 7 and 4-formylbenzoic acid.

Example 13

4-(4-Butyl-piperazine-1-carbonyl)-benzaldehyde

Prepared from the product of Example 8 and 4-formybenzoic acid.

Example 14

4-{4-(1-Methyl-heptyl)-piperazine-1-carbonyl}-benzaldehyde

Prepared from the product of Example 9 and 4-formylbenzoic acid.

Example 15

4-(4-Isopropyl-piperazine-1-carbonyl)-benzaldehyde

Prepared from the product of Example 10 and 4-formylbenzoic acid.

Example 16

4-(4-Methyl-piperazine-1-carbonyl)-benzaldehyde

Prepared from N-methylpiperazine and 4-formylbenzoic acid.

Example 17

3-(4-Methyl-piperazine-1-carbonyl)-benzaldehyde

Prepared from N-methylpiperazine and 4-formylbenzoic acid.

Example 18

3-(4-Isopropyl-piperazine-1-carbonyl)-benzaldehyde

Prepared from the product of Example 10 and 3-formylbenzoic acid.

Example 19

(4-Bromo-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone

To a solution of 4-bromobenzoic acid (500 mg) and the product of Example7 (710 mg) in DCM (20 mL) was added1-{3-(dimethylamino)propyl}-3-ethylcarbodiimide hydrochloride (713 mg),1-hydroxybenzotriazole hydrate (570 mg), and N-methyl morpholine (1.64mL). After 16 h the reaction mixture was treated with 1 N NaOH (25 mL)and extracted with DCM (3×75 mL). The organic layers were dried(Na₂SO₄), concentrated, and chromatographed on silica gel (1-3% 2 Mmethanolic ammonia/DCM) to give the title compound as white-yellow solid(630 mg).

Example 20

{4-(Benzylamino-methyl)-phenyl}-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone

To a solution of the product of Example 12 (150 mg) and benzylamine(0.062 mL) in DCM (5 mL) was added acetic acid (0.03 mL) and sodiumtriacetoxyborohydride (165 mg). After 16 h the reaction was treated with1 N NaOH (20 mL) and extracted with DCM (3×20 mL). The organic layerswere dried (Na₂SO₄), concentrated, and chromatographed (2-3% 2 Mmethanolic ammonia-DCM) to give the title compound as an oil (150 mg).

¹H NMR (400 MHz, CDCl₃): 7.40-7.34 (m, 8H), 7.29-7.26 (m, 1H), 3.85 (d,J=9.1 Hz, 4H), 3.75 (br s, 2H), 3.40 (br s, 2H), 2.59-2.45 (m, 4H),2.21-2.18 (m, 1H), 1.67 (s, 1H), 1.50-1.43 (m, 2H), 1.35-1.28 (m, 2H),0.92-0.89 (m, 6H).

The products of Example 21 through Example 42 were prepared in analogywith the procedure of Example 20 using the specified carbonyl compoundsand amines.

Example 21

(4-Azepan-1-ylmethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone

Prepared from the product of Example 12 and azepine.

¹H NMR (400 MHz, CDCl₃): 7.39-7.33 (m, 4H), 3.74 (br s, 2H), 3.65 (s,2H), 3.40 (br s, 2H), 2.62-2.46 (m, 8H), 2.21-2.17 (m, 1H), 1.62 (br s,8H), 1.50-1.43 (m, 2H), 1.34-1.27 (m, 2H), 0.92-0.89 (m, 6H).

Example 22

{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(decahydro-isoquinolin-2-ylmethyl)-phenyl}-methanone

Prepared from the product of Example 12 and decahydroisoquinoline.

¹H NMR (400 MHz, CDCl₃): 7.39-7.33 (m, 4H), 3.73 (br s, 2H), 3.52-3.39(m, 4H), 2.59-2.45 (m, 6H), 2.20-2.17 (m, 2H), 1.70-1.29 (m, 17H),0.92-0.88 (m, 6H).

Example 23

(4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone

Prepared from the product of Example 11 and azepine.

¹H NMR (400 MHz, CDCl₃): 7.35 (dd, J=9.1, 8.1 Hz, 4H), 3.76 (br s, 2H),3.63 (s, 2H), 3.42 (br s, 2H), 2.68-2.32 (m, 9H), 1.69-1.47 (m, 9H),1.36-1.20 (m, 1H), 0.96 (d, J=6.6, 3H), 0.89 (t, J=7.3, 3H).

Example 24

(4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone

Prepared from the product of Example 11 and dimethylamine hydrochloride.

¹H NMR (400 MHz, CDCl₃): 7.38-7.29 (m, 4H), 3.75 (br s, 2H), 3.42 (br s,4H), 2.66-2.30 (m, 5H), 2.22 (s, 6H), 1.58-1.46 (m, 1H), 1.34-1.20 (m,1H), 0.95 (d, J=6.57 Hz, 3H), 0.92-0.88 (m, 3H).

Example 25

(4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone

Prepared from the product of Example 11 and pyrrolidine.

¹H NMR (400 MHz, CDCl₃): 7.38-7.29 (m, 4H), 3.74 (br s, 2H), 3.60 (s,2H), 3.40 (br s, 2H), 2.64-2.34 (m, 9H), 1.81-1.70 (m, 4H), 1.59-1.45(m, 1H), 1.33-1.19 (m, 1H), 0.94 (d, J=6.57 Hz, 3H), 0.91-0.88 (m, 3H).

Example 26

{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone

Prepared from the product of Example 12 and pyrrolidine.

¹H NMR (400 MHz, CDCl₃): 7.41-7.35 (m, 4H), 3.73-3.70 (m, 4H), 3.38 (brs, 2H), 2.59-2.45 (m, 8H), 2.20-2.17 (m, 1H), 1.83 (br s, 4H), 1.49-1.27(m, 4H), 0.92-0.88 (m, 6H).

Example 27

{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone

Prepared from the product of Example 12 and piperidine.

¹H NMR (400 MHz, CDCl₃): 7.40-7.34 (m, 4H), 3.74 (br s, 2H), 3.53 (s,2H), 3.39 (br s, 2H), 2.59-2.42 (m, 8H), 2.20-2.17 (m, 1H), 1.62-1.60(m, 4H), 1.50-1.41 (m, 4H), 1.43-1.27 (m, 2H), 0.92-0.88 (m, 6H).

Example 28

(4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone

Prepared from the product of Example 11 and piperidine.

¹H NMR (400 MHz, CDCl₃): 7.36-7.30 (m, 4H), 3.75 (br s, 2H), 3.50-3.32(m, 4H), 2.55-2.24 (m, 9H), 1.60-1.48 (m, 5H), 1.46-1.36 (m, 2H),1.34-1.20 (m, 1H), 0.95 (d, J=6.6 Hz, 3H), 0.92-0.88 (m, 3H).

Example 29

(4-sec-Butyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanone

Prepared from the product of Example 11 and aniline.

¹H NMR (400 MHz, CDCl₃): 7.43-7.32 (m, 4H), 7.15 (tt, J=7.4, 5.4 Hz,2H), 6.74-6.66 (m, 1H), 6.59 (dd, J=7.6, 1.0 Hz, 2H), 4.33 (s, 2H), 4.2(br s, 1H), 3.76 (br s, 2H), 3.41 (br s, 2H), 2.66-2.27 (m, 5H),1.62-1.45 (m, 1H), 1.36-1.20 (m, 1H), 0.96 (d, J=6.6 Hz, 3H), 0.90 (t,J=7.4 Hz, 3H).

Example 30

(4-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone

Prepared from the product of Example 13 and dimethylamine hydrochloride.

¹H NMR (400 MHz, CDCl₃): 7.41-7.31 (m, 4H), 3.79 (br s, 2H), 3.43 (s,3H), 2.5 (br s, 2H), 2.37-2.34 (m, 3H), 2.24 (br s, 4H), 1.65 (br s,4H), 1.52-1.40 (m, 2H), 1.39-1.26 (m, 2H), 0.91 (t, J=7.3 Hz, 3H).

Example 31

(4-Butyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanone

Prepared from the product of Example 13 and4-trifluoromethyl-phenylamine.

¹H NMR (400 MHz, CDCl₃): 7.45-7.32 (m, 6H), 6.60 (d, J=8.5 Hz, 2H), 4.59(t, J=5.6 Hz, 1H), 4.39 (d, J=5.8 Hz, 2H), 3.79 (br s, 2H), 3.43 (br s,2H), 2.60-2.30 (m, 6H), 1.55-1.43 (m, 2H), 1.40-1.25 (m, 2H), 0.92 (t,J=7.3 Hz, 3H).

Example 32

{4-(1-Methyl-heptyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanone

Prepared from the product of Example 14 and morpholine.

¹H NMR (400 MHz, CDCl₃): 7.39-7.35 (m, 4H), 3.76 (br s, 2H), 3.68-3.66(m, 2H), 3.52 (s, 2H), 3.46 (br s, 2H), 2.64-2.45 (m, 10H), 1.51-1.47(m, 1H), 1.30-1.26 (m, 10H), 1.02 (m, 3H), 0.90-0.87 (m, 3H).

Example 33

{4-(1-Methyl-heptyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone

Prepared from the product of Example 14 and piperidine.

¹H NMR (400 MHz, CDCl₃): 7.42-7.35 (m, 4H), 3.77 (br s, 2H), 3.58 (s,2H), 3.42 (br s, 2H), 2.60-2.47 (m, 10H), 1.65 (br s, 4H), 1.50-1.46 (m,1H), 1.33-1.28 (m, 10H), 0.97 (d, J=6.5 Hz, 3H), 0.90-0.87 (m, 3H).

Example 34

(4-Isopropyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanone

Prepared from the product of Example 15 and 4-trifluoromethylaniline.

¹H NMR (400 MHz, CDCl₃): 7.41-7.36 (m, 6H), 6.62 (d, J=8.5 Hz, 2H),4.56-4.54 (m, 1H), 4.40 (d, J=5.8 Hz, 2H), 3.83 (br s, 2H), 3.48 (br s,2H), 2.80-2.77 (m, 1H), 2.63-2.50 (m, 4H), 1.08 (d, J=6.6 Hz, 6H).

Example 35

(4-Isopropyl-piperazin-1-yl)-{4-(4-isopropyl-piperazin-1-ylmethyl)-phenyl}-methanone

Prepared from the product of Example 15 and the product of Example 10.

¹H NMR (400 MHz, CDCl₃): 7.37 (m, 4H), 3.78 (br s, 2H), 3.54 (s, 2H),3.44 (br s, 2H), 2.76-2.45 (m, 14H), 1.11 (d, J=6.6 Hz, 6H), 1.05 (d,J=6.6 Hz, 6H).

Example 36

(4-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone

Prepared from the product of Example 13 and 3-trifluoromethylpiperidine.

¹H NMR (400 MHz, CDCl₃): 7.74-7.47 (m, 4H), 4.96-4.74 (m, 5H), 4.46-4.26(m, 2H), 4.00-3.38 (m, 5H), 2.97-2.69 (m, 6H), 2.04-1.58 (m, 4H),1.16-0.9 (m, 6H).

Example 37

(4-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone

Prepared from the product of Example 13 and morpholine.

¹H NMR (400 MHz, CDCl₃): 7.35-7.31 (m, 4H), 3.79 (br s, 2H), 3.68 (t,J=4.5 Hz, 4H), 3.48 (s, 2H), 3.41 (br s, 2H), 2.48 (br s, 2H),2.44-2.40, (m, 4H), 2.33 (t, J=7.6 Hz, 4H), 1.48-1.41 (m, 2H), 1.35-1.26(m, 2H), 0.89 (t, J=7.3 Hz, 3H).

Example 38

(4-Isopropyl-piperazin-1-yl)-(3-morpholin-4-ylmethyl-phenyl)-methanone

Prepared from the product of Example 18 and morpholine.

¹H NMR (400 MHz, CDCl₃): 7.39-7.28 (m, 4H), 3.79 (br s, 2H), 3.71 (t,J=4.6 Hz, 4H), 3.52 (s, 2H), 3.42 (br s, 2H), 2.76-2.70 (m, 1H), 2.60(br s, 2H), 2.46-2.44 (m, 6H), 1.05 (d, J=6.5 Hz, 6H).

Example 39

(4-Isopropyl-piperazin-1-yl)-(3-piperidin-1-ylmethyl-phenyl)-methanone

Prepared from the product of Example 18 and piperidine.

¹H NMR (400 MHz, CDCl₃): 7.37 (m, 3H), 7.28 (d, J=1.7 Hz, 1H), 3.79 (brs, 2H), 3.48 (s, 2H), 3.42 (br s, 2H), 2.76-2.69 (m, 1H), 2.69 (br s,2H), 2.45 (br s, 2H), 2.37 (br s, 2H), 1.59-1.54 (m, 4H), 1.44-1.42 (m,2H), 1.05 (d, J=6.5 Hz, 6H).

Example 40

(4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone

Prepared from the product of Example 15 and morpholine.

¹H NMR (400 MHz, CDCl₃): 7.36 (s, 4H), 3.79 (br s, 2H), 3.71 (t, J=4.7Hz, 4H), 3.51 (s, 2H), 3.44 (br s, 2H), 2.76-1.69 (m, 1H), 2.59 (br s,2H), 2.44 (t, J=4.4 Hz, 6H), 1.05 (d, J=6.5 Hz, 6H).

Example 41

(4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone

Prepared from the product of Example 15 and piperidine.

¹H NMR (400 MHz, CDCl₃): 7.35 (s, 4H), 3.79 (br s, 2H), 3.48 (br s, 2H),3.45 (br s, 2H), 2.72 (m, 1H), 2.59 (br s, 2H), 2.45 (br s, 2H), 2.38(br s, 4H), 1.60-1.55 (m, 4H), 1.48-1.40 (m, 2H), 1.06 (d, J=6.3 Hz,6H).

Example 42

{3-(4-Benzyl-piperidin-1-ylmethyl)-phenyl}-(4-methyl-piperazin-1-yl)-methanone

Prepared from the product of Example 17 and 4-benzylpiperidine.

¹H NMR (400 MHz, CDCl₃): 7.37-7.10 (m, 9H), 3.80 (br s, 2H), 3.48 (s,2H), 3.41 (br s, 2H), 2.87-2.79 (m, 2H), 2.53 (d, J=7.0 Hz, 2H), 2.47(br s, 2H), 2.33 (br s, 2H), 2.32 (s, 3H), 1.90 (ddd, J=11.7, 11.7, 2.2Hz, 2H), 1.63-1.45 (m, 3H), 1.35-1.23 (m, 2H).

Example 43

(4-Methyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride

To a solution of the product of Example 16 (60 mg) and morpholine (0.025mL) in DCM (5 mL) was added acetic acid (0.015 mL) and sodiumtriacetoxyborohydride (83 mg). After 16 h the reaction was treated with1 N NaOH (10 mL) and extracted with DCM (3×20 mL). Organic layers weredried (Na₂SO₄), concentrated under reduced pressure, and chromatographedon silica gel (4% 2 M methanolic ammonia/DCM) to give the free baseproduct. This material was converted into the dihydrochloride usingmethanol and 2 M HCl in ether to form a white solid (35 mg).

¹H NMR (400 MHz, CD₃OD): 7.71 (d, J=7.8 Hz, 2H), 7.62 (d, J=8.1 Hz, 2H),4.45 (s, 2H), 4.07-4.03 (m, 2H), 3.88-3.86 (m, 1H), 3.80 (t, J=11.6 Hz,2H), 3.62-3.39 (m, 6H), 3.27-3.17 (m, 5H), 2.96 (s, 3H).

The products of Example 44 through Example 62 were prepared in analogyto the procedure of Example 43 using the specified carbonyl compoundsand amines.

Example 44

(4-Isopropyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-pyridin-2-ylamino)-methyl}-phenyl}-methanonedihydrochloride

Prepared from the product of Example 15 and4-trifluoromethyl-pyridin-2-ylamine.

¹H NMR (400 MHz, CD₃OD): 8.08-8.06 (m, 1H), 7.58-7.45 (m, 4H), 7.39-7.35(m, 1H), 7.14-7.10 (m, 1H), 4.76-4.70 (m, 2H), 3.58 (br s, 6H),3.25-3.23 (m, 2H), 1.41-1.30 (m, 7H).

Example 45

{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-phenylaminomethyl-phenyl)-methanonedihydrochloride

Prepared from the product of Example 12 and aniline.

¹H NMR (400 MHz, CD₃SOCD₃): 7.76-7.63 (m, 4H), 7.53-7.41 (tt, J=7.3, 6.6Hz, 2H), 7.03 (t, J=7.2 Hz, 1H), 6.92 (dd, J=7.6, 1.1 Hz, 2H), 5.60 (s,1H), 4.66 (br s, 2H), 4.47 (br s, 1H), 4.05 (br s, 2H), 3.70 (br s, 2H),2.90 (br s, 2H), 2.76 (br s, 2H), 1.84-1.70 (m, 2H), 1.68-1.55 (m, 2H),1.30-1.20 (m, 6H).

Example 46

(4-Dimethylaminomethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanonedihydrochloride

Prepared from the product of Example 12 and dimethylamine hydrochloride.

¹H NMR (400 MHz, CD₃OD): 7.78-7.44 (m, 4H), 4.52 (br s, 1H), 4.32-4.25(m, 2H), 3.83-3.58 (m, 2H), 3.23-2.93 (m, 4H), 2.78-2.55 (m, 6H),2.54-2.35 (m, 2H), 2.00-1.71 (m, 2H), 1.70-1.47 (m, 2H), 1.05-0.77 (m,6H).

Example 47

{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanonedihydrochloride

Prepared from the product of Example 12 and 4-trifluoromethylaniline.

¹H NMR (400 MHz, CD₃OD): 7.56-7.12 (m, 6H), 6.69-6.49 (m, 2H), 4.81 (s,2H), 4.47-4.28 (m, 2H), 3.37-3.03 (m, 8H), 1.97-1.56 (m, 4H), 1.13-0.89(m, 6H).

Example 48

{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride

Prepared from the product of Example 12 and morpholine.

¹H NMR (400 MHz, dmso-d₆): 7.74 (d, J=8.1 Hz, 2H), 7.55 (d, J=8.1 Hz,2H), 4.36 (d, J=4.8 Hz, 2H), 4.00-3.67 (m, 10H), 3.52-3.41 (m, 2H),3.25-3.18 (m, 2H), 3.11-2.99 (m, 3H), 1.97-1.80 (m, 2H), 1.69-1.52 (m,2H), 0.96 (t, J=7.58 Hz, 6H).

Example 49

{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride

Prepared from the product of Example 12 and 3-trifluoromethylpiperidine.

¹H NMR (400 MHz, CD₃OD): 7.72 (d, J=8.1 Hz, 2H), 7.64 (d, J=7.8, 2H),4.87 (s, 2H), 4.50-4.40 (m, 2H), 3.75-3.41 (m, 8H), 3.20-2.84 (m, 4H),2.09 (m, 2H), 2.00-1.50 (m, 6H), 1.12-1.02 (m, 6H).

Example 50

(4-sec-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride

Prepared from the product of Example 11 and 3-trifluoromethylpiperidine.

¹H NMR (400 MHz, CD₃OD): 7.71 (d, J=8.3 Hz, 2H), 7.63 (d, J=8.1 Hz, 2H),4.86 (s, 2H), 4.52-4.40 (m, 2H), 3.75-3.45 (m, 8H), 3.23-2.96 (m, 5H),2.17-2.00 (br m, 2H), 1.97-1.54 (m, 4H), 1.50-1.25 (m, 2H), 1.10-0.98(m, 3H).

Example 51

(4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride

Prepared from the product of Example 11 and morpholine.

¹H NMR (400 MHz, CD₃OD): 7.71-7.62 (m, 4H), 4.43 (s, 2H), 4.14-3.59 (m,7H), 3.52-3.11 (m, 10H), 2.02-1.88 (m, 1H), 1.68-1.49 (m, 1H), 1.38 (d,J=6.6 Hz, 3H), 1.04 (t, J=7.3 Hz, 3H).

Example 52

(4-Isopropyl-piperazin-1-yl)-{4-{(6-trifluoromethyl-pyridin-3-ylamino)-methyl}-phenyl}-methanonedihydrochloride

Prepared from the product of Example 15 and6-trifluoromethyl-pyridin-3-ylamine.

¹H NMR (400 MHz, CD₃OD): 8.18-8.11 (m, 1H), 7.81-7.74 (m, 1H), 7.53-7.46(m, 5H), 4.92-4.89 (m, 2H), 4.58-4.51 (m, 2H), 3.56-3.52 (m, 4H),3.28-3.21 (m, 2H), 1.40-1.46 (m, 7H).

Example 53

{4-{(5-Chloro-pyridin-2-ylamino)-methyl}-phenyl}-(4-isopropyl-piperazin-1-yl)-methanone dihydrochloride

Prepared from the product of Example 15 and 5-chloro-pyridin-2-ylamine.

¹H NMR (400 MHz, CD₃OD): 8.04 (d, J=2.5 Hz, 1H), 7.38-7.33 (m, 5H), 6.32(d, J=8.8 Hz, 1H), 5.05 (t, J=5.6 Hz, 1H), 4.52 (d, J=6.1 Hz, 2H), 3.78(br s, 2H), 3.43 (br s, 2H), 2.72 (m, 1H), 2.58-2.44 (m, 4H), 1.04 (d,J=6.6 Hz, 6H).

Example 54

(4-Methyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanonedihydrochloride

Prepared from the product of Example 16 and piperidine.

¹H NMR (400 MHz, CD₃OD): 7.68-7.60 (m, 4H), 4.36 (s, 2H), 3.73 (br s,2H), 3.52-3.46 (m, 4H), 3.25 (br s, 4H), 3.00 (br s, 2H), 2.87 (s, 3H),1.94-1.82 (m, 5H), 1.53 (br s, 1H).

Example 55

(4-Isopropyl-piperazin-1-yl)-{4-{(5-trifluoromethyl-pyridin-2-ylamino)-methyl}-phenyl}-methanonedihydrochloride

Prepared from the product of Example 15 and5-trifluoromethyl-pyridin-2-ylamine.

¹H NMR (400 MHz, CD₃OD): 8.31 (s, 1H), 8.12 (d, J=8.3 Hz, 1H), 7.57 (s,4H), 7.24 (d, J=9.6 Hz, 1H), 4.75 (s, 2H), 3.60-3.46 (m, 6H), 3.24-3.21(m, 2H), 1.41-1.40 (m, 7H).

Example 56

(4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride

Prepared from the product of Example 15 and3-trifluoromethyl-piperidine.

¹H NMR (400 MHz, CD₃OD): 7.74-7.64 (m, 4H), 4.88 (s, 2H), 4.52-4.41 (m,2H), 3.70-3.50 (m, 6H), 3.26-3.13 (m, 4H), 3.07-2.92 (m, 2H), 2.14-2.07(m, 2H), 1.94-1.84 (m, 1H), 1.68-1.58 (m, 1H), 1.42-1.39 (m, 6H).

Example 57

(4-Diethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride

Prepared from the product of Example 15 and diethylamine.

¹H NMR (400 MHz, CD₃OD): 7.70-7.64 (m, 4H), 4.42 (s, 2H), 3.61-3.57 (m,6H), 3.25-3.22 (m, 6H), 1.42-1.30 (m, 13H).

Example 58

{4-(Benzylamino-methyl)-phenyl}-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride

Prepared from the product of Example 15 and benzylamine.

¹H NMR (400 MHz, CD₃OD): 7.67-7.43 (m, 9H), 4.33 (s, 2H) 4.29 (s, 2H),3.61-3.56 (m, 6H), 3.26-3.22 (m, 2H), 1.42-1.41 (d, J=6.6 Hz, 7H).

Example 59

(4-Isopropyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanonedihydrochloride

Prepared from the product of Example 15 and aniline.

¹H NMR (400 MHz, CD₃OD): 7.57-7.54 (m, 7H), 7.47-7.44 (m, 2H), 4.69 (s,2H), 3.62-3.52 (m, 6H), 3.25-3.19 (m, 2H), 1.42-1.41 (d, J=6.6 Hz, 7H).

Example 60

(4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride

Prepared from the product of Example 15 and azepane.

¹H NMR (400 MHz, CD₃OD): 7.69 (d, J=8.2 Hz, 2H), 7.63 (d, J=8.1 Hz, 2H),4.43 (s, 2H), 3.60-3.43 (m, 8H), 3.23-3.20 (m, 4H), 1.97-1.90 (m, 4H),1.79-1.73 (m, 4H), 1.42-1.46 (d, J=6.6 Hz, 7H).

Example 61

(4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanonedihydrochloride

Prepared from the product of Example 15 and pyrrolidine.

¹H NMR (400 MHz, CD₃OD): 7.69 (d, J=8.3 Hz, 2H), 7.63 (d, J=8.2 Hz, 2H),4.46 (s, 2H), 3.61-3.51 (m, 8H), 3.25-3.20 (m, 4H), 2.22-2.18 (m, 2H),2.06-2.03 (m, 2H), 1.42 (d, J=6.6 Hz, 7H).

Example 62

(4-Dimethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride

Prepared from the product of Example 15 and dimethylamine hydrochloride.

¹H NMR (400 MHz, CD₃OD): 7.66 (br s, 4H), 4.40 (s, 2H), 3.65-3.54 (m,4H), 3.26-3.20 (m, 4H), 2.89 (br s, 6H), 1.41 (d, J=6.6 Hz, 7H).

Example 63

4-Cyclohexyl-piperazine-1-carboxylic acid tert-butyl ester

Prepared in analogy to Example 1 from piperazine-1-carboxylic acidtert-butyl ester and cyclohexanone.

Example 64

1-Cyclohexyl-piperazine dihydrochloride

Prepared in analogy to Example 6 from the product of Example 63.

Example 65

4-(4-Cyclohexyl-piperazine-1-carbonyl)-benzaldehyde

Prepared in analogy to Example 11 from the product of Example 64.

The products of Example 66 through Example 72 were prepared in analogyto the procedure of Example 20 from the specified carbonyl compounds andamines.

Example 66

(4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone

Prepared from the product of Example 65 and piperidine.

¹H NMR (400 MHz, CDCl₃): 7.35 (s, 4H), 3.78 (br s, 2H), 3.48 (s, 2H),3.44 (br s, 2H), 2.64-2.51 (m, 4H), 2.37 (br s, 2H), 2.30-2.29 (m, 2H),1.86-1.80 (m, 4H), 1.65-1.55 (m, 7H), 1.45-1.44 (m, 2H), 1.24-1.19 (m,4H).

Example 67

(4-Isopropyl-piperazin-1-yl)-(4-thiomorpholin-4-ylmethyl-phenyl)-methanone

Prepared from the product of Example 15 and thiomorpholine.

¹H NMR (400 MHz, CDCl₃): 7.40-7.30 (m, 4H), 3.90-3.68 (br m, 2H), 3.53(s, 2H), 3.49-3.37 (br m, 2H), 2.81-2.63 (m, 9H), 2.63-2.52 (br m, 2H),2.51-2.35 (br m, 2H), 1.05 (d, J=6.5 Hz, 6H).

Example 68

(4-Isopropyl-piperazin-1-yl)-(4-{[(2-methoxy-ethyl)-propyl-amino]-methyl}-phenyl)-methanone

Prepared from the product of Example 15 and(2-methoxy-ethyl)-propyl-amine.

¹H NMR (500 MHz, CDCl₃): 7.41-7.34 (m, 4H), 3.79 (br s, 2H), 3.65 (s,2H), 3.51-3.46 (m, 4H), 3.32 (s, 3H), 2.76-2.71 (m, 1H), 2.69-2.65 (m,2H), 2.53 (br s, 2H), 2.46-2.43 (m, 4H), 1.67 (br s, 1H), 1.53-1.46 (m,2H), 1.06 (d, J=6.5 Hz, 6H), 0.868 (t, J=7.3 Hz, 3H).

Example 69

(4-{[Ethyl-(2-methoxy-ethyl)-amino]-methyl}-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone

Prepared from the product of Example 15 and(2-methoxy-ethyl)-ethyl-amine.

¹H NMR (400 MHz, CDCl₃): 7.42-7.31 (m, 4H), 3.79 (br s, 2H), 3.70 (s,2H), 3.53-3.45 (m, 4H), 3.33 (s, 3H), 2.76-2.71 (m, 1H), 2.69-2.67 (m,2H), 2.60-2.56 (m, 4H), 2.46 (s, 2H), 1.62 (br s, 1H), 1.11-1.01 (m,8H).

Example 70

(4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-ethylamino)-methyl]-phenyl}-methanone

Prepared from the product of Example 15 and (2-methoxy-ethyl)-amine.

¹H NMR (400 MHz, CDCl₃): 7.36 (m, 4H), 3.84 (s, 2H), 3.75 (br s, 2H),3.53-3.51 (m, 2H), 3.42 (br s, 2H), 3.62 (s, 3H), 2.81-2.79 (m, 2H),2.77-2.74 (m, 1H), 2.62 (br s, 2H), 2.42 (br s, 2H), 1.70 (br s, 1H),1.05 (d, J=6.5 Hz, 6H).

Example 71

(4-Isopropyl-piperazin-1-yl)-[4-(pyridin-2-ylaminomethyl)-phenyl]-methanone

Prepared from the product of Example of 15 and 2-aminopyridine.

¹H NMR (400 MHz, CDCl₃): 8.16-8.10 (m, 1H), 7.46-7.36 (m, 5H), 6.65-6.59(m, 1H), 6.42-6.36 (m, 1H), 5.04 (t, J=6.1 Hz, 1H), 4.57 (d, J=5.9 Hz,2H), 3.91-3.68 (br m, 2H), 3.56-3.36 (br m, 2H), 2.80-2.67 (m, 1H),2.69-2.54 (br m, 2H), 2.53-2.34 (br m, 2H), 1.07 (d, J=6.6 Hz, 6H).

Example 72

(4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-1-methyl-ethylamino)-methyl]-phenyl}-methanone

Prepared from the product of example 15 and2-methoxy-1-methyl-ethylamine.

¹H NMR (500 MHz, CDCl₃): 7.35-7.38 (m, 4H), 3.89 (d, J=13.3, 1H),3.82-3.75 (m, 3H), 3.45 (br s, 2H), 3.43-3.32 (m, 4H), 3.28-3.25 (m,1H), 2.96-2.92 (m, 1H), 2.75-2.58 (m, 1H), 2.65-2.20 (m, 5H), 1.06-1.04(m, 9H).

Biological Methods In Vitro

Transfection of Cells with Human Histamine Receptor

A 10 cm tissue culture dish with a confluent monolayer of SK-N-MC cellswas split two days prior to transfection. Using sterile technique themedia was removed and the cells were detached from the dish by theaddition of trypsin. One fifth of the cells were then placed onto a new10 cm dish. Cells were grown in a 37° C. incubator with 5% CO₂ inMinimal Essential Media Eagle with 10% Fetal Bovine Serum. After twodays cells were approximately 80% confluent. These were removed from thedish with trypsin and pelleted in a clinical centrifuge. The pellet wasthen re-suspended in 400 μL complete media and transferred to anelectroporation cuvette with a 0.4 cm gap between the electrodes. Onemicrogram of supercoiled H₃ receptor cDNA was added to the cells andmixed. The voltage for the electroporation was set at 0.25 kV, thecapacitance was set at 960 μF. After electroporation the cells werediluted into 10 mL complete media and plated onto four 10 cm dishes.Because of the variability in the efficiency of electroporation, fourdifferent concentrations of cells were plated. The ratios used were;1:20, 1:10, 1:5, with the remainder of the cells being added to thefourth dish. The cells were allowed to recover for 24 h before addingthe selection media (complete media with 600 μg/mL G418). After 10 daysdishes were analyzed for surviving colonies of cells. Dishes withwell-isolated colonies were used. Cells from individual colonies wereisolated and tested. SK-N-MC cells were used because they give efficientcoupling for inhibition of adenylate cyclase. The clones that gave themost robust inhibition of adenylate cyclase in response to histaminewere used for further study.

{³H}-N-methylhistamine Binding

Cell pellets from histamine H₃ receptor-expressing SK-N-MC cells werehomogenized in 20 mM Tris HCl/0.5 mM EDTA. Supernatants from an 800 gspin were collected, recentrifuged at 30,000 g for 30 min. Pellets werere-homogenized in 50 mM Tris/5 mM EDTA (pH 7.4). Membranes wereincubated with 0.8 nM {³H}-N-methylhistamine plus/minus test compoundsfor 45 min at 25° C. and harvested by rapid filtration over GF/C glassfiber filters (pretreated with 0.3% polyethylenimine) followed by fourwashes with ice-cold buffer. Filters were dried, added to 4 mLscintillation cocktail and then counted on a liquid scintillationcounter. Non-specific binding was defined with 10 μM histamine. ThepK_(i) values were calculated based on a K_(d) of 800 μM and a ligandconcentration ({L}) of 800 pM according to the formula:K _(i)=(IC ₅₀)/(1+({L}/(K _(d)))

K_(i) values for exemplary compounds of the invention are listed in thetable below: EX K_(i) (nM) 20 2.0 21 2.0 22 2.0 23 0.9 24 1.5 25 1.0 260.9 27 0.4 28 0.9 29 38 30 18 31 630 32 130 33 52 34 68 35 18 36 12 37 938 180 39 35 40 3.0 41 0.7 42 800 43 22 44 85 45 54 46 2.0 47 81 48 1 494 50 30 51 2 52 14 53 30 54 24 55 49 56 1.0 57 6.0 58 3.0 59 23 60 1.061 1.0 62 5.0 66 1 67 2 68 2 69 3 70 2 71 4 72 3

F. OTHER EMBODIMENTS

The features and advantages of the invention will be apparent to one ofordinary skill in view of the discussion, examples, embodiments, andclaims relating to the invention. The invention also contemplatesvariations and adaptations, based on the disclosure herein concerningthe key features and advantages of the invention, and within theabilities of one of ordinary skill.

1. A composition comprising a compound of formula (I):

wherein R¹ is C₁₋₁₀ alkyl, C₃₋₈ alkenyl, C₃₋₈ cycloalkyl, (C₃₋₈cycloalkyl)C₁₋₆ alkyl, (C₃₋₈ cycloalkyl)C₃₋₈ alkenyl, or (C₁₋₈alkylcarbonyl)C₁₋₈ alkyl; n is 1 or 2; X is O or S; one of R², R³ and R⁴is G and the other two independently are hydrogen, fluoro, chloro,bromo, nitro, trifluoromethyl, methyl, or C₁₋₃alkoxy; G is LQ; L isunbranched —(CH₂)_(m)— wherein m is an integer from 1 to 7; Q is NR⁸R⁹wherein R⁸ is independently selected from hydrogen, C₁₋₆ alkyl, C₃₋₆alkenyl, 3-9 membered carbocyclyl, 3-12 membered heterocyclyl, phenyl,(6-9-membered heterocyclyl)C₁₋₆ alkylene, and (phenyl)C₁₋₆ alkylene; andR⁹ is independently selected from C₁₋₆ alkyl, C₃₋₆ alkenyl, 6-9 memberedcarbocyclyl, 3-12 membered heterocyclyl, phenyl, (6-9-memberedheterocyclyl)C₁₋₆ alkylene, and (phenyl)C₁₋₆ alkylene; or Q is asaturated 3-12 membered N-linked heterocyclyl, wherein, in addition tothe N-linking nitrogen, the 3-12 membered heterocyclyl may optionallycontain between 1 and 3 additional heteroatoms independently selectedfrom O, S, and NH; wherein Q is optionally substituted with 1-3substituents independently selected from the group consisting ofhydroxy, halo, carboxamide, C₁₋₆ alkyl, 5-9 membered or 6-9 memberedheterocyclyl, —N(C₁₋₆ alkyl)(5-9 membered or 6-9 membered heterocyclyl),—NH(5-9 membered or 6-9 membered heterocyclyl), —O(5-9 or 6-9 memberedheterocyclyl), (5-9 membered or 6-9 membered heterocyclyl)C₁₋₃ alkylene,C₁₋₆ alkoxy, (C₃₋₆ cycloalkyl)-O—, phenyl, (phenyl)C₁₋₃ alkylene, and(phenyl)C₁₋₃ alkylene-O—, where each of above heterocyclyl, phenyl, andalkyl groups may be optionally substituted with from 1 to 3 substituentsindependently selected from trifluoromethyl, methoxy, halo, nitro,cyano, hydroxy, and C₁₋₃ alkyl; provided however that when R¹ is methyl,G is not piperidin-1-ylmethyl; and wherein each of the above alkyl,alkylene, alkenyl, heterocyclyl, cycloalkyl, carbocyclyl, and arylgroups may each be independently and optionally substituted with between1 and 3 substituents independently selected from trifluoromethyl,methoxy, halo, amino, nitro, hydroxy, and C₁₋₃ alkyl; or apharmaceutically acceptable salt, ester, tautomer, solvate or amidethereof.
 2. A compound of claim 1, wherein R¹ is C₁₋₁₀ alkyl.
 3. Acompound of claim 1, wherein R¹ is C₃₋₅ alkyl.
 4. A compound of claim 1,wherein R¹ is isopropyl.
 5. A compound of claim 1 wherein n is
 1. 6. Acompound of claim 1, wherein X is O.
 7. A compound of claim 1, whereinone of R³ and R⁴ is G.
 8. A compound of claim 1, wherein R⁴ is G.
 9. Acompound of claim 1, wherein L is unbranched —(CH₂)_(m)—, wherein m isan integer from 1 to
 4. 10. A compound of claim 1, wherein L is —CH₂—.11. A compound of claim 1, wherein L is —CH₂CH₂—.
 12. A compound ofclaim 1 wherein Q is a saturated N-linked nitrogen-containingheterocyclyl.
 13. A compound of claim 1, wherein Q is selected fromsubstituted or unsubstituted piperidinyl, diazepanyl, azepanyl,decahydroisoquinolin-2-yl, piperazinyl, pyrrolinyl, pyrrolidinyl,thiomorpholinyl, or morpholinyl.
 14. A compound of claim 1, wherein Q isunsubstituted piperidinyl, diazepanyl, azepanyl,decahydroisoquinolin-2-yl, piperazinyl, pyrrolinyl, pyrrolidinyl,thiomorpholinyl, or morpholinyl.
 15. A compound of claim 14, wherein Qis unsubstituted diazepanyl, azepanyl, morpholinyl,decahydroisoquinolin-2-yl, piperidinyl, or pyrrolidinyl;
 16. A compoundof claim 1, wherein substituted Q are selected from N—(C₁₋₆alkyl)piperazinyl, N-phenyl-piperazinyl, 1,3,8-triaza-spiro{4.5}decyl,and 1,4-dioxa-8-aza-spiro{4.5}decyl.
 17. A compound of claim 1, whereinQ is a monovalent radical of an amine selected from aziridine,1,4,7-trioxa-10-aza-cyclododecane, thiazolidine,1-phenyl-1,3,8-triaza-spiro{4.5}decan-4-one, piperidine-3-carboxylicacid diethylamide, 1,2,3,4,5,6-hexahydro-{2,3′}bipyridinyl,4-(3-trifluoromethyl-phenyl)-piperazine, 2-piperazin-1-yl-pyrimidine,piperidine-4-carboxylic acid amide, methyl-(2-pyridin-2-yl-ethyl)-amine,{2-(3,4-dimethoxy-phenyl)-ethyl}-methyl-amine, thiomorpholinyl,allyl-cyclopentyl-amine, {2-(1H-indol-3-yl)-ethyl}-methyl-amine,1-piperidin-4-yl-1,3-dihydro-benzoimidazol-2-one,2-(piperidin-4-yloxy)-pyrimidine, piperidin-4-yl-pyridin-2-yl-amine,phenylamine, pyridin-2-ylamine.
 18. A compound of claim 1, wherein Q isselected from diazepanyl, azepanyl, morpholinyl, piperidinyl, andpyrrolidinyl, optionally substituted with between 1 and 3 substituentsselected from hydroxy, halo, carboxamide, C₁₋₆ alkyl, 5-9 membered or6-9 membered heterocyclyl, —N(C₁₋₆ alkyl)(5-9 membered or 6-9 memberedheterocyclyl), —NH(5-9 membered or 6-9 membered heterocyclyl), —O(5-9 or6-9 membered heterocyclyl), (5-9 membered or 6-9 memberedheterocyclyl)C₁₋₃ alkylene, C₁₋₆ alkoxy, (C₃₋₆ cycloalkyl)-O—, phenyl,(phenyl)C₁₋₃ alkylene, and (phenyl)C₁₋₃ alkylene-O—, where each of aboveheterocyclyl, phenyl, and alkyl groups may be optionally substitutedwith from 1 to 3 substituents independently selected fromtrifluoromethyl, methoxy, halo, nitro, cyano, hydroxy, and C₁₋₃ alkyl.19. A compound of claim 12, wherein Q is substituted with a substituentcomprising a 5-9 membered heterocyclyl group selected from: pyridyl,pyrimidyl, furyl, thiofuryl, imidazolyl, (imidazolyl)C₁₋₆ alkylene,oxazolyl, thiazolyl, 2,3-dihydro-indolyl, benzimidazolyl,2-oxobenzimidazolyl, (tetrazolyl)C₁₋₆ alkylene, tetrazolyl,(triazolyl)C₁₋₆ alkylene, triazolyl, (pyrrolyl)C₁₋₆ alkylene,pyrrolidinyl, and pyrrolyl.
 20. A compound of claim 19, wherein Q ispiperidinyl.
 21. A compound of claim 1, wherein R⁸ is hydrogen.
 22. Acompound of claim 1, wherein R⁹ is C₁₋₆ alkyl.
 23. A compound of claim1, wherein R⁹ is unsubstituted or substituted phenyl.
 24. A compound ofclaim 1, wherein R⁸ and R⁹ independently are C₁₋₆ alkyl.
 25. A compoundof claim 1, wherein R⁸ and R⁹ are methyl.
 26. A compound of claim 1,wherein R⁸ and R⁹ are ethyl.
 27. A compound of claim 21, wherein R⁹ isselected from phenyl or 5-9 membered aromatic heterocyclyl, wherein saidphenyl or aromatic heterocyclyl is optionally substituted with 1-3substituents selected from methoxy, hydroxy, halo, nitro, cyano,trifluoromethyl, and C₁₋₃ alkyl.
 28. A compound of claim 27, wherein R⁹is selected from substituted or unsubstituted phenyl, pyridyl,pyrimidyl, furyl, thiofuryl, imidazolyl, (imidazolyl)C₁₋₆ alkylene,oxazolyl, thiazolyl, 2,3-dihydro-indolyl, benzimidazolyl,2-oxobenzimidazolyl, (tetrazolyl)C₁₋₆ alkylene, tetrazolyl,(triazolyl)C₁₋₆ alkylene, triazolyl, (pyrrolyl)C₁₋₆ alkylene,pyrrolidinyl, and pyrrolyl.
 29. A compound of claim 28, wherein R⁹ isphenyl.
 30. A compound of claim 28, wherein R⁹ is substituted orunsubstituted pyridyl.
 31. A compound of claim 1 wherein R¹ is C₁₋₁₀alkyl; X is O; R⁴ is G; L is —CH₂—; and Q is a saturated N-linkednitrogen-containing heterocyclyl.
 32. A compound of claim 31 wherein R¹is branched.
 33. A compound of claim 31 wherein R¹ is C₃₋₅ alkyl.
 34. Acompound of claim 31, wherein R¹ is isopropyl.
 35. A compound of claim31, wherein Q is selected from substituted or unsubstituted piperidinyl,diazepanyl, azepanyl, decahydroisoquinolin-2-yl, piperazinyl,pyrrolinyl, pyrrolidinyl, thiomorpholinyl, or morpholinyl.
 36. Acompound of claim 31, wherein Q is unsubstituted azepanyl, diazepanyl,morpholinyl, decahydroisoquinolin-2-yl, piperidinyl, or pyrrolidinyl.37. A compound of claim 1 selected from the group consisting of:(4-{[Ethyl-(2-methoxy-ethyl)-amino]-methyl}-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone;(4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;(4-Azepan-1-ylmethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;(4-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;(4-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;(4-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone;(4-Butyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanone;(4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-Diethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Dimethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Dimethylaminomethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-(3-morpholin-4-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(3-piperidin-1-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-{[(2-methoxy-ethyl)-propyl-amino]-methyl}-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-(4-thiomorpholin-4-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-{4-(4-isopropyl-piperazin-1-ylmethyl)-phenyl}-methanone;(4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-ethylamino)-methyl]-phenyl}-methanone;(4-Isopropyl-piperazin-1-yl)-[4-(pyridin-2-ylaminomethyl)-phenyl]-methanone;(4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-1-methyl-ethylamino)-methyl]-phenyl}-methanone;(4-Isopropyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanone;(4-Isopropyl-piperazin-1-yl)-{4-{(4-trifluoromethyl-pyridin-2-ylamino)-methyl}-phenyl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-{4-{(5-trifluoromethyl-pyridin-2-ylamino)-methyl}-phenyl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-{4-{(6-trifluoromethyl-pyridin-3-ylamino)-methyl}-phenyl}-methanonedihydrochloride;(4-Methyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;(4-Methyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanonedihydrochloride;(4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;(4-sec-Butyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;{3-(4-Benzyl-piperidin-1-ylmethyl)-phenyl}-(4-methyl-piperazin-1-yl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-phenylaminomethyl-phenyl)-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(decahydro-isoquinolin-2-ylmethyl)-phenyl}-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-{(4-trifluoromethyl-phenylamino)-methyl}-phenyl}-methanonedihydrochloride;{4-(1-Methyl-heptyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanone;{4-(1-Methyl-heptyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;{4-(Benzylamino-methyl)-phenyl}-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;{4-(Benzylamino-methyl)-phenyl}-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;and{4-{(5-Chloro-pyridin-2-ylamino)-methyl}-phenyl}-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride.
 38. A compound of claim 1 selected from the groupconsisting of:(4-{[Ethyl-(2-methoxy-ethyl)-amino]-methyl}-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone;(4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;(4-Azepan-1-ylmethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;(4-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;(4-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;(4-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanone;(4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-Diethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Dimethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Dimethylaminomethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-(3-piperidin-1-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-{[(2-methoxy-ethyl)-propyl-amino]-methyl}-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone5 dihydrochloride;(4-Isopropyl-piperazin-1-yl)-(4-thiomorpholin-4-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-{4-(4-isopropyl-piperazin-1-ylmethyl)-phenyl}-methanone;(4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-ethylamino)-methyl]-phenyl}-methanone;(4-Isopropyl-piperazin-1-yl)-[4-(pyridin-2-ylaminomethyl)-phenyl]-methanone;(4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-1-methyl-ethylamino)-methyl]-phenyl}-methanone;(4-Isopropyl-piperazin-1-yl)-{4-{(5-trifluoromethyl-pyridin-2-ylamino)-methyl}-phenyl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-{4-{(6-trifluoromethyl-pyridin-3-ylamino)-methyl}-phenyl}-methanonedihydrochloride;(4-Methyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;(4-Methyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanonedihydrochloride;(4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;(4-sec-Butyl-piperazin-1-yl)-(4-phenylaminomethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(decahydro-isoquinolin-2-ylmethyl)-phenyl}-methanone;{4-(Benzylamino-methyl)-phenyl}-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;{4-(Benzylamino-methyl)-phenyl}-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;and{4-{(5-Chloro-pyridin-2-ylamino)-methyl}-phenyl}-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride.
 39. A compound of claim 1 selected from the groupconsisting of:(4-{[Ethyl-(2-methoxy-ethyl)-amino]-methyl}-phenyl)-(4-isopropyl-piperazin-1-yl)-methanone;(4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;(4-Azepan-1-ylmethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone;(4-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;(4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-Diethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Dimethylaminomethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Dimethylaminomethyl-phenyl)-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-(4-{[(2-methoxy-ethyl)-propyl-amino]-methyl}-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-(4-thiomorpholin-4-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-ethylamino)-methyl]-phenyl}-methanone;(4-Isopropyl-piperazin-1-yl)-[4-(pyridin-2-ylaminomethyl)-phenyl]-methanone;(4-Isopropyl-piperazin-1-yl)-{4-[(2-methoxy-1-methyl-ethylamino)-methyl]-phenyl}-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;(4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-{4-(decahydro-isoquinolin-2-ylmethyl)-phenyl}-methanone;{4-(Benzylamino-methyl)-phenyl}-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride; and{4-(Benzylamino-methyl)-phenyl}-{4-(1-ethyl-propyl)-piperazin-1-yl}-methanone.40. A compound of claim 1 selected from the group consisting of:(4-Azepan-1-ylmethyl-phenyl)-(4-isopropyl-piperazin-1-yl)-methanonedihydrochloride;(4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;(4-Cyclohexyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanonedihydrochloride;(4-Isopropyl-piperazin-1-yl)-{4-(3-trifluoromethyl-piperidin-1-ylmethyl)-phenyl}-methanonedihydrochloride;(4-sec-Butyl-piperazin-1-yl)-(4-dimethylaminomethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;and{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone.41. A compound of claim 1 selected from the group consisting of:(4-Azepan-1-ylmethyl-phenyl)-(4-sec-butyl-piperazin-1-yl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-piperidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-piperidin-1-ylmethyl-phenyl)-methanone;{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-pyrrolidin-1-ylmethyl-phenyl)-methanone;(4-Isopropyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanone;(4-sec-Butyl-piperazin-1-yl)-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride; and{4-(1-Ethyl-propyl)-piperazin-1-yl}-(4-morpholin-4-ylmethyl-phenyl)-methanonedihydrochloride.
 42. A pharmaceutical composition, comprising a compoundof claim 1 and a pharmaceutically-acceptable excipient.
 43. A compoundof claim 1 isotopically-labelled to be detectable by PET or SPECT.
 44. Amethod of inhibiting histamine H₃ receptor activity in a subject,comprising administering an effective amount of a compound of claim 1 toa subject in need of such inhibition of histamine H₃ receptor activity.45. A method of treating a subject having a disease or conditionmodulated by histamine H₃ receptor activity, comprising administering tothe subject a therapeutically effective amount of a compound of claim 1.46. A method of claim 45, wherein said disease or condition is selectedfrom the group consisting of sleep/wake disorders, arousal/vigilancedisorders, migraine, asthma, dementia, cognitive dysfunction, neurogenicinflammation, mild cognitive impairment (pre-dementia), Alzheimer'sdisease, epilepsy, narcolepsy, eating disorders, obesity, motionsickness, vertigo, attention deficit hyperactivity disorders, learningdisorders, memory retention disorders, schizophrenia, substance abuse,bipolar disorders, manic disorders and depression, nasal congestion,itch, allergic rhinitis, and upper airway allergic response.
 47. Amethod for treating a disease or condition modulated by at least onereceptor selected from the histamine H₁ receptor and the histamine H₃receptor, said method comprising (a) administering to a subject ajointly effective amount of a histamine H₁ receptor antagonist compound,and (b) administering to the subject a jointly effective amount of acompound of claim 1, said method providing a jointly therapeuticallyeffective amount of said compounds.
 48. The method of claim 47 whereinthe histamine H₁ receptor antagonist and the compound of claim 1 arepresent in the same dosage form.
 49. A method for treating diseases orconditions modulated by at least one receptor selected from thehistamine H₂ receptor and the histamine H₃ receptor in a subject,comprising (a) administering to the subject a jointly effective amountof a histamine H₂ receptor antagonist compound, and (b) administering tothe subject a jointly effective amount of a compound of claim 1, saidmethod providing a jointly therapeutically effective amount of saidcompounds.
 50. The method of claim 39 wherein the histamine H₂ receptorantagonist and the compound of claim 1 are present in the same dosageform.
 51. A method for treating one or more disorders or conditionsselected from the group consisting of sleep/wake disorders, narcolepsy,and arousal/vigilance disorders, comprising administering to a subject atherapeutically effective amount of a compound of claim
 1. 52. A methodfor treating attention deficit hyperactivity disorders (ADHD),comprising administering to a subject a therapeutically effective amountof a compound of claim
 1. 53. A method for treating one or moredisorders or conditions selected from the group consisting of dementia,mild cognitive impairment (pre-dementia), cognitive dysfunction,schizophrenia, depression, manic disorders, bipolar disorders, andlearning and memory disorders, comprising administering to a subject atherapeutically effective amount of a compound of claim
 1. 54. A methodfor treating or preventing upper airway allergic response, itch, nasalcongestion, or allergic rhinitis, comprising administering to a subjecta therapeutically effective amount of a compound of claim
 1. 55. Amethod for studying disorders mediated by the histamine H₃ receptor,comprising using an ¹⁸F-labeled or ¹¹C-labelled compound of claim 1 as apositron emission tomography (PET) molecular probe.